Rename Python 3 markdown files into 'python'

```
for f in $(find . -iname "*python3*" | grep -vE 'git'); do
  fnew=$(echo "$f" | sed 's/python3/python/')
  git mv "$f" "$fnew"
done

1 files changed, 0 insertions, 1042 deletions

diff --git a/python3.html.markdown b/python3.html.markdown
deleted file mode 100644
index f69ffb14..00000000
--- a/python3.html.markdown
+++ /dev/null
@@ -1,1042 +0,0 @@
----
-language: python3
-contributors:
-    - ["Louie Dinh", "http://pythonpracticeprojects.com"]
-    - ["Steven Basart", "http://github.com/xksteven"]
-    - ["Andre Polykanine", "https://github.com/Oire"]
-    - ["Zachary Ferguson", "http://github.com/zfergus2"]
-    - ["evuez", "http://github.com/evuez"]
-    - ["Rommel Martinez", "https://ebzzry.io"]
-    - ["Roberto Fernandez Diaz", "https://github.com/robertofd1995"]
-    - ["caminsha", "https://github.com/caminsha"]
-filename: learnpython3.py
----
-
-Python was created by Guido van Rossum in the early 90s. It is now one of the most popular
-languages in existence. I fell in love with Python for its syntactic clarity. It's basically
-executable pseudocode.
-
-Note: This article applies to Python 3 specifically. Check out [here](http://learnxinyminutes.com/docs/python/) if you want to learn the old Python 2.7
-
-```python
-
-# Single line comments start with a number symbol.
-
-""" Multiline strings can be written
-    using three "s, and are often used
-    as documentation.
-"""
-
-####################################################
-## 1. Primitive Datatypes and Operators
-####################################################
-
-# You have numbers
-3  # => 3
-
-# Math is what you would expect
-1 + 1   # => 2
-8 - 1   # => 7
-10 * 2  # => 20
-35 / 5  # => 7.0
-
-# Integer division rounds down for both positive and negative numbers.
-5 // 3       # => 1
--5 // 3      # => -2
-5.0 // 3.0   # => 1.0 # works on floats too
--5.0 // 3.0  # => -2.0
-
-# The result of division is always a float
-10.0 / 3  # => 3.3333333333333335
-
-# Modulo operation
-7 % 3  # => 1
-
-# Exponentiation (x**y, x to the yth power)
-2**3  # => 8
-
-# Enforce precedence with parentheses
-1 + 3 * 2  # => 7
-(1 + 3) * 2  # => 8
-
-# Boolean values are primitives (Note: the capitalization)
-True  # => True
-False  # => False
-
-# negate with not
-not True   # => False
-not False  # => True
-
-# Boolean Operators
-# Note "and" and "or" are case-sensitive
-True and False  # => False
-False or True   # => True
-
-# True and False are actually 1 and 0 but with different keywords
-True + True # => 2
-True * 8    # => 8
-False - 5   # => -5
-
-# Comparison operators look at the numerical value of True and False
-0 == False  # => True
-1 == True   # => True
-2 == True   # => False
--5 != False # => True
-
-# Using boolean logical operators on ints casts them to booleans for evaluation, but their non-cast value is returned
-# Don't mix up with bool(ints) and bitwise and/or (&,|)
-bool(0)     # => False
-bool(4)     # => True
-bool(-6)    # => True
-0 and 2     # => 0
--5 or 0     # => -5
-
-# Equality is ==
-1 == 1  # => True
-2 == 1  # => False
-
-# Inequality is !=
-1 != 1  # => False
-2 != 1  # => True
-
-# More comparisons
-1 < 10  # => True
-1 > 10  # => False
-2 <= 2  # => True
-2 >= 2  # => True
-
-# Seeing whether a value is in a range
-1 < 2 and 2 < 3  # => True
-2 < 3 and 3 < 2  # => False
-# Chaining makes this look nicer
-1 < 2 < 3  # => True
-2 < 3 < 2  # => False
-
-# (is vs. ==) is checks if two variables refer to the same object, but == checks
-# if the objects pointed to have the same values.
-a = [1, 2, 3, 4]  # Point a at a new list, [1, 2, 3, 4]
-b = a             # Point b at what a is pointing to
-b is a            # => True, a and b refer to the same object
-b == a            # => True, a's and b's objects are equal
-b = [1, 2, 3, 4]  # Point b at a new list, [1, 2, 3, 4]
-b is a            # => False, a and b do not refer to the same object
-b == a            # => True, a's and b's objects are equal
-
-# Strings are created with " or '
-"This is a string."
-'This is also a string.'
-
-# Strings can be added too! But try not to do this.
-"Hello " + "world!"  # => "Hello world!"
-# String literals (but not variables) can be concatenated without using '+'
-"Hello " "world!"    # => "Hello world!"
-
-# A string can be treated like a list of characters
-"This is a string"[0]  # => 'T'
-
-# You can find the length of a string
-len("This is a string")  # => 16
-
-# You can also format using f-strings or formatted string literals (in Python 3.6+)
-name = "Reiko"
-f"She said her name is {name}." # => "She said her name is Reiko"
-# You can basically put any Python statement inside the braces and it will be output in the string.
-f"{name} is {len(name)} characters long." # => "Reiko is 5 characters long."
-
-
-# None is an object
-None  # => None
-
-# Don't use the equality "==" symbol to compare objects to None
-# Use "is" instead. This checks for equality of object identity.
-"etc" is None  # => False
-None is None   # => True
-
-# None, 0, and empty strings/lists/dicts/tuples all evaluate to False.
-# All other values are True
-bool(0)   # => False
-bool("")  # => False
-bool([])  # => False
-bool({})  # => False
-bool(())  # => False
-
-####################################################
-## 2. Variables and Collections
-####################################################
-
-# Python has a print function
-print("I'm Python. Nice to meet you!")  # => I'm Python. Nice to meet you!
-
-# By default the print function also prints out a newline at the end.
-# Use the optional argument end to change the end string.
-print("Hello, World", end="!")  # => Hello, World!
-
-# Simple way to get input data from console
-input_string_var = input("Enter some data: ") # Returns the data as a string
-# Note: In earlier versions of Python, input() method was named as raw_input()
-
-# There are no declarations, only assignments.
-# Convention is to use lower_case_with_underscores
-some_var = 5
-some_var  # => 5
-
-# Accessing a previously unassigned variable is an exception.
-# See Control Flow to learn more about exception handling.
-some_unknown_var  # Raises a NameError
-
-# if can be used as an expression
-# Equivalent of C's '?:' ternary operator
-"yahoo!" if 3 > 2 else 2  # => "yahoo!"
-
-# Lists store sequences
-li = []
-# You can start with a prefilled list
-other_li = [4, 5, 6]
-
-# Add stuff to the end of a list with append
-li.append(1)    # li is now [1]
-li.append(2)    # li is now [1, 2]
-li.append(4)    # li is now [1, 2, 4]
-li.append(3)    # li is now [1, 2, 4, 3]
-# Remove from the end with pop
-li.pop()        # => 3 and li is now [1, 2, 4]
-# Let's put it back
-li.append(3)    # li is now [1, 2, 4, 3] again.
-
-# Access a list like you would any array
-li[0]   # => 1
-# Look at the last element
-li[-1]  # => 3
-
-# Looking out of bounds is an IndexError
-li[4]  # Raises an IndexError
-
-# You can look at ranges with slice syntax.
-# The start index is included, the end index is not
-# (It's a closed/open range for you mathy types.)
-li[1:3]   # Return list from index 1 to 3 => [2, 4]
-li[2:]    # Return list starting from index 2 => [4, 3]
-li[:3]    # Return list from beginning until index 3  => [1, 2, 4]
-li[::2]   # Return list selecting every second entry => [1, 4]
-li[::-1]  # Return list in reverse order => [3, 4, 2, 1]
-# Use any combination of these to make advanced slices
-# li[start:end:step]
-
-# Make a one layer deep copy using slices
-li2 = li[:]  # => li2 = [1, 2, 4, 3] but (li2 is li) will result in false.
-
-# Remove arbitrary elements from a list with "del"
-del li[2]  # li is now [1, 2, 3]
-
-# Remove first occurrence of a value
-li.remove(2)  # li is now [1, 3]
-li.remove(2)  # Raises a ValueError as 2 is not in the list
-
-# Insert an element at a specific index
-li.insert(1, 2)  # li is now [1, 2, 3] again
-
-# Get the index of the first item found matching the argument
-li.index(2)  # => 1
-li.index(4)  # Raises a ValueError as 4 is not in the list
-
-# You can add lists
-# Note: values for li and for other_li are not modified.
-li + other_li  # => [1, 2, 3, 4, 5, 6]
-
-# Concatenate lists with "extend()"
-li.extend(other_li)  # Now li is [1, 2, 3, 4, 5, 6]
-
-# Check for existence in a list with "in"
-1 in li  # => True
-
-# Examine the length with "len()"
-len(li)  # => 6
-
-
-# Tuples are like lists but are immutable.
-tup = (1, 2, 3)
-tup[0]      # => 1
-tup[0] = 3  # Raises a TypeError
-
-# Note that a tuple of length one has to have a comma after the last element but
-# tuples of other lengths, even zero, do not.
-type((1))   # => <class 'int'>
-type((1,))  # => <class 'tuple'>
-type(())    # => <class 'tuple'>
-
-# You can do most of the list operations on tuples too
-len(tup)         # => 3
-tup + (4, 5, 6)  # => (1, 2, 3, 4, 5, 6)
-tup[:2]          # => (1, 2)
-2 in tup         # => True
-
-# You can unpack tuples (or lists) into variables
-a, b, c = (1, 2, 3)  # a is now 1, b is now 2 and c is now 3
-# You can also do extended unpacking
-a, *b, c = (1, 2, 3, 4)  # a is now 1, b is now [2, 3] and c is now 4
-# Tuples are created by default if you leave out the parentheses
-d, e, f = 4, 5, 6  # tuple 4, 5, 6 is unpacked into variables d, e and f
-# respectively such that d = 4, e = 5 and f = 6
-# Now look how easy it is to swap two values
-e, d = d, e  # d is now 5 and e is now 4
-
-
-# Dictionaries store mappings from keys to values
-empty_dict = {}
-# Here is a prefilled dictionary
-filled_dict = {"one": 1, "two": 2, "three": 3}
-
-# Note keys for dictionaries have to be immutable types. This is to ensure that
-# the key can be converted to a constant hash value for quick look-ups.
-# Immutable types include ints, floats, strings, tuples.
-invalid_dict = {[1,2,3]: "123"}  # => Raises a TypeError: unhashable type: 'list'
-valid_dict = {(1,2,3):[1,2,3]}   # Values can be of any type, however.
-
-# Look up values with []
-filled_dict["one"]  # => 1
-
-# Get all keys as an iterable with "keys()". We need to wrap the call in list()
-# to turn it into a list. We'll talk about those later.  Note - for Python
-# versions <3.7, dictionary key ordering is not guaranteed. Your results might
-# not match the example below exactly. However, as of Python 3.7, dictionary
-# items maintain the order at which they are inserted into the dictionary.
-list(filled_dict.keys())  # => ["three", "two", "one"] in Python <3.7
-list(filled_dict.keys())  # => ["one", "two", "three"] in Python 3.7+
-
-
-# Get all values as an iterable with "values()". Once again we need to wrap it
-# in list() to get it out of the iterable. Note - Same as above regarding key
-# ordering.
-list(filled_dict.values())  # => [3, 2, 1]  in Python <3.7
-list(filled_dict.values())  # => [1, 2, 3] in Python 3.7+
-
-# Check for existence of keys in a dictionary with "in"
-"one" in filled_dict  # => True
-1 in filled_dict      # => False
-
-# Looking up a non-existing key is a KeyError
-filled_dict["four"]  # KeyError
-
-# Use "get()" method to avoid the KeyError
-filled_dict.get("one")      # => 1
-filled_dict.get("four")     # => None
-# The get method supports a default argument when the value is missing
-filled_dict.get("one", 4)   # => 1
-filled_dict.get("four", 4)  # => 4
-
-# "setdefault()" inserts into a dictionary only if the given key isn't present
-filled_dict.setdefault("five", 5)  # filled_dict["five"] is set to 5
-filled_dict.setdefault("five", 6)  # filled_dict["five"] is still 5
-
-# Adding to a dictionary
-filled_dict.update({"four":4})  # => {"one": 1, "two": 2, "three": 3, "four": 4}
-filled_dict["four"] = 4         # another way to add to dict
-
-# Remove keys from a dictionary with del
-del filled_dict["one"]  # Removes the key "one" from filled dict
-
-# From Python 3.5 you can also use the additional unpacking options
-{'a': 1, **{'b': 2}}  # => {'a': 1, 'b': 2}
-{'a': 1, **{'a': 2}}  # => {'a': 2}
-
-
-
-# Sets store ... well sets
-empty_set = set()
-# Initialize a set with a bunch of values. Yeah, it looks a bit like a dict. Sorry.
-some_set = {1, 1, 2, 2, 3, 4}  # some_set is now {1, 2, 3, 4}
-
-# Similar to keys of a dictionary, elements of a set have to be immutable.
-invalid_set = {[1], 1}  # => Raises a TypeError: unhashable type: 'list'
-valid_set = {(1,), 1}
-
-# Add one more item to the set
-filled_set = some_set
-filled_set.add(5)  # filled_set is now {1, 2, 3, 4, 5}
-# Sets do not have duplicate elements
-filled_set.add(5)  # it remains as before {1, 2, 3, 4, 5}
-
-# Do set intersection with &
-other_set = {3, 4, 5, 6}
-filled_set & other_set  # => {3, 4, 5}
-
-# Do set union with |
-filled_set | other_set  # => {1, 2, 3, 4, 5, 6}
-
-# Do set difference with -
-{1, 2, 3, 4} - {2, 3, 5}  # => {1, 4}
-
-# Do set symmetric difference with ^
-{1, 2, 3, 4} ^ {2, 3, 5}  # => {1, 4, 5}
-
-# Check if set on the left is a superset of set on the right
-{1, 2} >= {1, 2, 3} # => False
-
-# Check if set on the left is a subset of set on the right
-{1, 2} <= {1, 2, 3} # => True
-
-# Check for existence in a set with in
-2 in filled_set   # => True
-10 in filled_set  # => False
-
-# Make a one layer deep copy
-filled_set = some_set.copy()  # filled_set is {1, 2, 3, 4, 5}
-filled_set is some_set        # => False
-
-
-####################################################
-## 3. Control Flow and Iterables
-####################################################
-
-# Let's just make a variable
-some_var = 5
-
-# Here is an if statement. Indentation is significant in Python!
-# Convention is to use four spaces, not tabs.
-# This prints "some_var is smaller than 10"
-if some_var > 10:
-    print("some_var is totally bigger than 10.")
-elif some_var < 10:    # This elif clause is optional.
-    print("some_var is smaller than 10.")
-else:                  # This is optional too.
-    print("some_var is indeed 10.")
-
-
-"""
-For loops iterate over lists
-prints:
-    dog is a mammal
-    cat is a mammal
-    mouse is a mammal
-"""
-for animal in ["dog", "cat", "mouse"]:
-    # You can use format() to interpolate formatted strings
-    print("{} is a mammal".format(animal))
-
-"""
-"range(number)" returns an iterable of numbers
-from zero to the given number
-prints:
-    0
-    1
-    2
-    3
-"""
-for i in range(4):
-    print(i)
-
-"""
-"range(lower, upper)" returns an iterable of numbers
-from the lower number to the upper number
-prints:
-    4
-    5
-    6
-    7
-"""
-for i in range(4, 8):
-    print(i)
-
-"""
-"range(lower, upper, step)" returns an iterable of numbers
-from the lower number to the upper number, while incrementing
-by step. If step is not indicated, the default value is 1.
-prints:
-    4
-    6
-"""
-for i in range(4, 8, 2):
-    print(i)
-
-"""
-To loop over a list, and retrieve both the index and the value of each item in the list
-prints:
-    0 dog
-    1 cat
-    2 mouse
-"""
-animals = ["dog", "cat", "mouse"]
-for i, value in enumerate(animals):
-    print(i, value)
-
-"""
-While loops go until a condition is no longer met.
-prints:
-    0
-    1
-    2
-    3
-"""
-x = 0
-while x < 4:
-    print(x)
-    x += 1  # Shorthand for x = x + 1
-
-# Handle exceptions with a try/except block
-try:
-    # Use "raise" to raise an error
-    raise IndexError("This is an index error")
-except IndexError as e:
-    pass                 # Pass is just a no-op. Usually you would do recovery here.
-except (TypeError, NameError):
-    pass                 # Multiple exceptions can be handled together, if required.
-else:                    # Optional clause to the try/except block. Must follow all except blocks
-    print("All good!")   # Runs only if the code in try raises no exceptions
-finally:                 #  Execute under all circumstances
-    print("We can clean up resources here")
-
-# Instead of try/finally to cleanup resources you can use a with statement
-with open("myfile.txt") as f:
-    for line in f:
-        print(line)
-
-# Writing to a file
-contents = {"aa": 12, "bb": 21}
-with open("myfile1.txt", "w+") as file:
-    file.write(str(contents))        # writes a string to a file
-
-with open("myfile2.txt", "w+") as file:
-    file.write(json.dumps(contents)) # writes an object to a file
-
-# Reading from a file
-with open('myfile1.txt', "r+") as file:
-    contents = file.read()           # reads a string from a file
-print(contents)
-# print: {"aa": 12, "bb": 21}
-
-with open('myfile2.txt', "r+") as file:
-    contents = json.load(file)       # reads a json object from a file
-print(contents)     
-# print: {"aa": 12, "bb": 21}
-
-
-# Python offers a fundamental abstraction called the Iterable.
-# An iterable is an object that can be treated as a sequence.
-# The object returned by the range function, is an iterable.
-
-filled_dict = {"one": 1, "two": 2, "three": 3}
-our_iterable = filled_dict.keys()
-print(our_iterable)  # => dict_keys(['one', 'two', 'three']). This is an object that implements our Iterable interface.
-
-# We can loop over it.
-for i in our_iterable:
-    print(i)  # Prints one, two, three
-
-# However we cannot address elements by index.
-our_iterable[1]  # Raises a TypeError
-
-# An iterable is an object that knows how to create an iterator.
-our_iterator = iter(our_iterable)
-
-# Our iterator is an object that can remember the state as we traverse through it.
-# We get the next object with "next()".
-next(our_iterator)  # => "one"
-
-# It maintains state as we iterate.
-next(our_iterator)  # => "two"
-next(our_iterator)  # => "three"
-
-# After the iterator has returned all of its data, it raises a StopIteration exception
-next(our_iterator)  # Raises StopIteration
-
-# We can also loop over it, in fact, "for" does this implicitly!
-our_iterator = iter(our_iterable)
-for i in our_iterator:
-    print(i)  # Prints one, two, three
-
-# You can grab all the elements of an iterable or iterator by calling list() on it.
-list(our_iterable)  # => Returns ["one", "two", "three"]
-list(our_iterator)  # => Returns [] because state is saved
-
-
-####################################################
-## 4. Functions
-####################################################
-
-# Use "def" to create new functions
-def add(x, y):
-    print("x is {} and y is {}".format(x, y))
-    return x + y  # Return values with a return statement
-
-# Calling functions with parameters
-add(5, 6)  # => prints out "x is 5 and y is 6" and returns 11
-
-# Another way to call functions is with keyword arguments
-add(y=6, x=5)  # Keyword arguments can arrive in any order.
-
-# You can define functions that take a variable number of
-# positional arguments
-def varargs(*args):
-    return args
-
-varargs(1, 2, 3)  # => (1, 2, 3)
-
-# You can define functions that take a variable number of
-# keyword arguments, as well
-def keyword_args(**kwargs):
-    return kwargs
-
-# Let's call it to see what happens
-keyword_args(big="foot", loch="ness")  # => {"big": "foot", "loch": "ness"}
-
-
-# You can do both at once, if you like
-def all_the_args(*args, **kwargs):
-    print(args)
-    print(kwargs)
-"""
-all_the_args(1, 2, a=3, b=4) prints:
-    (1, 2)
-    {"a": 3, "b": 4}
-"""
-
-# When calling functions, you can do the opposite of args/kwargs!
-# Use * to expand tuples and use ** to expand kwargs.
-args = (1, 2, 3, 4)
-kwargs = {"a": 3, "b": 4}
-all_the_args(*args)            # equivalent to all_the_args(1, 2, 3, 4)
-all_the_args(**kwargs)         # equivalent to all_the_args(a=3, b=4)
-all_the_args(*args, **kwargs)  # equivalent to all_the_args(1, 2, 3, 4, a=3, b=4)
-
-# Returning multiple values (with tuple assignments)
-def swap(x, y):
-    return y, x  # Return multiple values as a tuple without the parenthesis.
-                 # (Note: parenthesis have been excluded but can be included)
-
-x = 1
-y = 2
-x, y = swap(x, y)     # => x = 2, y = 1
-# (x, y) = swap(x,y)  # Again parenthesis have been excluded but can be included.
-
-# Function Scope
-x = 5
-
-def set_x(num):
-    # Local var x not the same as global variable x
-    x = num    # => 43
-    print(x)   # => 43
-
-def set_global_x(num):
-    global x
-    print(x)   # => 5
-    x = num    # global var x is now set to 6
-    print(x)   # => 6
-
-set_x(43)
-set_global_x(6)
-
-
-# Python has first class functions
-def create_adder(x):
-    def adder(y):
-        return x + y
-    return adder
-
-add_10 = create_adder(10)
-add_10(3)   # => 13
-
-# There are also anonymous functions
-(lambda x: x > 2)(3)                  # => True
-(lambda x, y: x ** 2 + y ** 2)(2, 1)  # => 5
-
-# There are built-in higher order functions
-list(map(add_10, [1, 2, 3]))          # => [11, 12, 13]
-list(map(max, [1, 2, 3], [4, 2, 1]))  # => [4, 2, 3]
-
-list(filter(lambda x: x > 5, [3, 4, 5, 6, 7]))  # => [6, 7]
-
-# We can use list comprehensions for nice maps and filters
-# List comprehension stores the output as a list which can itself be a nested list
-[add_10(i) for i in [1, 2, 3]]         # => [11, 12, 13]
-[x for x in [3, 4, 5, 6, 7] if x > 5]  # => [6, 7]
-
-# You can construct set and dict comprehensions as well.
-{x for x in 'abcddeef' if x not in 'abc'}  # => {'d', 'e', 'f'}
-{x: x**2 for x in range(5)}  # => {0: 0, 1: 1, 2: 4, 3: 9, 4: 16}
-
-
-####################################################
-## 5. Modules
-####################################################
-
-# You can import modules
-import math
-print(math.sqrt(16))  # => 4.0
-
-# You can get specific functions from a module
-from math import ceil, floor
-print(ceil(3.7))   # => 4.0
-print(floor(3.7))  # => 3.0
-
-# You can import all functions from a module.
-# Warning: this is not recommended
-from math import *
-
-# You can shorten module names
-import math as m
-math.sqrt(16) == m.sqrt(16)  # => True
-
-# Python modules are just ordinary Python files. You
-# can write your own, and import them. The name of the
-# module is the same as the name of the file.
-
-# You can find out which functions and attributes
-# are defined in a module.
-import math
-dir(math)
-
-# If you have a Python script named math.py in the same
-# folder as your current script, the file math.py will
-# be loaded instead of the built-in Python module.
-# This happens because the local folder has priority
-# over Python's built-in libraries.
-
-
-####################################################
-## 6. Classes
-####################################################
-
-# We use the "class" statement to create a class
-class Human:
-
-    # A class attribute. It is shared by all instances of this class
-    species = "H. sapiens"
-
-    # Basic initializer, this is called when this class is instantiated.
-    # Note that the double leading and trailing underscores denote objects
-    # or attributes that are used by Python but that live in user-controlled
-    # namespaces. Methods(or objects or attributes) like: __init__, __str__,
-    # __repr__ etc. are called special methods (or sometimes called dunder methods)
-    # You should not invent such names on your own.
-    def __init__(self, name):
-        # Assign the argument to the instance's name attribute
-        self.name = name
-
-        # Initialize property
-        self._age = 0
-
-    # An instance method. All methods take "self" as the first argument
-    def say(self, msg):
-        print("{name}: {message}".format(name=self.name, message=msg))
-
-    # Another instance method
-    def sing(self):
-        return 'yo... yo... microphone check... one two... one two...'
-
-    # A class method is shared among all instances
-    # They are called with the calling class as the first argument
-    @classmethod
-    def get_species(cls):
-        return cls.species
-
-    # A static method is called without a class or instance reference
-    @staticmethod
-    def grunt():
-        return "*grunt*"
-
-    # A property is just like a getter.
-    # It turns the method age() into an read-only attribute of the same name.
-    # There's no need to write trivial getters and setters in Python, though.
-    @property
-    def age(self):
-        return self._age
-
-    # This allows the property to be set
-    @age.setter
-    def age(self, age):
-        self._age = age
-
-    # This allows the property to be deleted
-    @age.deleter
-    def age(self):
-        del self._age
-
-
-# When a Python interpreter reads a source file it executes all its code.
-# This __name__ check makes sure this code block is only executed when this
-# module is the main program.
-if __name__ == '__main__':
-    # Instantiate a class
-    i = Human(name="Ian")
-    i.say("hi")                     # "Ian: hi"
-    j = Human("Joel")
-    j.say("hello")                  # "Joel: hello"
-    # i and j are instances of type Human, or in other words: they are Human objects
-
-    # Call our class method
-    i.say(i.get_species())          # "Ian: H. sapiens"
-    # Change the shared attribute
-    Human.species = "H. neanderthalensis"
-    i.say(i.get_species())          # => "Ian: H. neanderthalensis"
-    j.say(j.get_species())          # => "Joel: H. neanderthalensis"
-
-    # Call the static method
-    print(Human.grunt())            # => "*grunt*"
-    
-    # Cannot call static method with instance of object 
-    # because i.grunt() will automatically put "self" (the object i) as an argument
-    print(i.grunt())                # => TypeError: grunt() takes 0 positional arguments but 1 was given
-                                    
-    # Update the property for this instance
-    i.age = 42
-    # Get the property
-    i.say(i.age)                    # => "Ian: 42"
-    j.say(j.age)                    # => "Joel: 0"
-    # Delete the property
-    del i.age
-    # i.age                         # => this would raise an AttributeError
-
-
-####################################################
-## 6.1 Inheritance
-####################################################
-
-# Inheritance allows new child classes to be defined that inherit methods and
-# variables from their parent class. 
-
-# Using the Human class defined above as the base or parent class, we can
-# define a child class, Superhero, which inherits the class variables like
-# "species", "name", and "age", as well as methods, like "sing" and "grunt"
-# from the Human class, but can also have its own unique properties.
-
-# To take advantage of modularization by file you could place the classes above in their own files,
-# say, human.py
-
-# To import functions from other files use the following format
-# from "filename-without-extension" import "function-or-class"
-
-from human import Human
-
-
-# Specify the parent class(es) as parameters to the class definition
-class Superhero(Human):
-
-    # If the child class should inherit all of the parent's definitions without
-    # any modifications, you can just use the "pass" keyword (and nothing else)
-    # but in this case it is commented out to allow for a unique child class:
-    # pass
-
-    # Child classes can override their parents' attributes
-    species = 'Superhuman'
-
-    # Children automatically inherit their parent class's constructor including
-    # its arguments, but can also define additional arguments or definitions
-    # and override its methods such as the class constructor.
-    # This constructor inherits the "name" argument from the "Human" class and
-    # adds the "superpower" and "movie" arguments:
-    def __init__(self, name, movie=False,
-                 superpowers=["super strength", "bulletproofing"]):
-
-        # add additional class attributes:
-        self.fictional = True
-        self.movie = movie
-        # be aware of mutable default values, since defaults are shared
-        self.superpowers = superpowers
-
-        # The "super" function lets you access the parent class's methods
-        # that are overridden by the child, in this case, the __init__ method.
-        # This calls the parent class constructor:
-        super().__init__(name)
-
-    # override the sing method
-    def sing(self):
-        return 'Dun, dun, DUN!'
-
-    # add an additional instance method
-    def boast(self):
-        for power in self.superpowers:
-            print("I wield the power of {pow}!".format(pow=power))
-
-
-if __name__ == '__main__':
-    sup = Superhero(name="Tick")
-
-    # Instance type checks
-    if isinstance(sup, Human):
-        print('I am human')
-    if type(sup) is Superhero:
-        print('I am a superhero')
-
-    # Get the Method Resolution search Order used by both getattr() and super()
-    # This attribute is dynamic and can be updated
-    print(Superhero.__mro__)    # => (<class '__main__.Superhero'>,
-                                # => <class 'human.Human'>, <class 'object'>)
-
-    # Calls parent method but uses its own class attribute
-    print(sup.get_species())    # => Superhuman
-
-    # Calls overridden method
-    print(sup.sing())           # => Dun, dun, DUN!
-
-    # Calls method from Human
-    sup.say('Spoon')            # => Tick: Spoon
-
-    # Call method that exists only in Superhero
-    sup.boast()                 # => I wield the power of super strength!
-                                # => I wield the power of bulletproofing!
-
-    # Inherited class attribute
-    sup.age = 31
-    print(sup.age)              # => 31
-
-    # Attribute that only exists within Superhero
-    print('Am I Oscar eligible? ' + str(sup.movie))
-
-####################################################
-## 6.2 Multiple Inheritance
-####################################################
-
-# Another class definition
-# bat.py
-class Bat:
-
-    species = 'Baty'
-
-    def __init__(self, can_fly=True):
-        self.fly = can_fly
-
-    # This class also has a say method
-    def say(self, msg):
-        msg = '... ... ...'
-        return msg
-
-    # And its own method as well
-    def sonar(self):
-        return '))) ... ((('
-
-if __name__ == '__main__':
-    b = Bat()
-    print(b.say('hello'))
-    print(b.fly)
-
-
-# And yet another class definition that inherits from Superhero and Bat
-# superhero.py
-from superhero import Superhero
-from bat import Bat
-
-# Define Batman as a child that inherits from both Superhero and Bat
-class Batman(Superhero, Bat):
-
-    def __init__(self, *args, **kwargs):
-        # Typically to inherit attributes you have to call super:
-        # super(Batman, self).__init__(*args, **kwargs)      
-        # However we are dealing with multiple inheritance here, and super()
-        # only works with the next base class in the MRO list.
-        # So instead we explicitly call __init__ for all ancestors.
-        # The use of *args and **kwargs allows for a clean way to pass arguments,
-        # with each parent "peeling a layer of the onion".
-        Superhero.__init__(self, 'anonymous', movie=True, 
-                           superpowers=['Wealthy'], *args, **kwargs)
-        Bat.__init__(self, *args, can_fly=False, **kwargs)
-        # override the value for the name attribute
-        self.name = 'Sad Affleck'
-
-    def sing(self):
-        return 'nan nan nan nan nan batman!'
-
-
-if __name__ == '__main__':
-    sup = Batman()
-
-    # Get the Method Resolution search Order used by both getattr() and super().
-    # This attribute is dynamic and can be updated
-    print(Batman.__mro__)       # => (<class '__main__.Batman'>, 
-                                # => <class 'superhero.Superhero'>, 
-                                # => <class 'human.Human'>, 
-                                # => <class 'bat.Bat'>, <class 'object'>)
-
-    # Calls parent method but uses its own class attribute
-    print(sup.get_species())    # => Superhuman
-
-    # Calls overridden method
-    print(sup.sing())           # => nan nan nan nan nan batman!
-
-    # Calls method from Human, because inheritance order matters
-    sup.say('I agree')          # => Sad Affleck: I agree
-
-    # Call method that exists only in 2nd ancestor
-    print(sup.sonar())          # => ))) ... (((
-
-    # Inherited class attribute
-    sup.age = 100
-    print(sup.age)              # => 100
-
-    # Inherited attribute from 2nd ancestor whose default value was overridden.
-    print('Can I fly? ' + str(sup.fly)) # => Can I fly? False
-
-
-
-####################################################
-## 7. Advanced
-####################################################
-
-# Generators help you make lazy code.
-def double_numbers(iterable):
-    for i in iterable:
-        yield i + i
-
-# Generators are memory-efficient because they only load the data needed to
-# process the next value in the iterable. This allows them to perform
-# operations on otherwise prohibitively large value ranges.
-# NOTE: `range` replaces `xrange` in Python 3.
-for i in double_numbers(range(1, 900000000)):  # `range` is a generator.
-    print(i)
-    if i >= 30:
-        break
-
-# Just as you can create a list comprehension, you can create generator
-# comprehensions as well.
-values = (-x for x in [1,2,3,4,5])
-for x in values:
-    print(x)  # prints -1 -2 -3 -4 -5 to console/terminal
-
-# You can also cast a generator comprehension directly to a list.
-values = (-x for x in [1,2,3,4,5])
-gen_to_list = list(values)
-print(gen_to_list)  # => [-1, -2, -3, -4, -5]
-
-
-# Decorators
-# In this example `beg` wraps `say`. If say_please is True then it
-# will change the returned message.
-from functools import wraps
-
-
-def beg(target_function):
-    @wraps(target_function)
-    def wrapper(*args, **kwargs):
-        msg, say_please = target_function(*args, **kwargs)
-        if say_please:
-            return "{} {}".format(msg, "Please! I am poor :(")
-        return msg
-
-    return wrapper
-
-
-@beg
-def say(say_please=False):
-    msg = "Can you buy me a beer?"
-    return msg, say_please
-
-
-print(say())                 # Can you buy me a beer?
-print(say(say_please=True))  # Can you buy me a beer? Please! I am poor :(
-```
-
-## Ready For More?
-
-### Free Online
-
-* [Automate the Boring Stuff with Python](https://automatetheboringstuff.com)
-* [Ideas for Python Projects](http://pythonpracticeprojects.com)
-* [The Official Docs](http://docs.python.org/3/)
-* [Hitchhiker's Guide to Python](http://docs.python-guide.org/en/latest/)
-* [Python Course](http://www.python-course.eu/index.php)
-* [First Steps With Python](https://realpython.com/learn/python-first-steps/)
-* [A curated list of awesome Python frameworks, libraries and software](https://github.com/vinta/awesome-python)
-* [30 Python Language Features and Tricks You May Not Know About](http://sahandsaba.com/thirty-python-language-features-and-tricks-you-may-not-know.html)
-* [Official Style Guide for Python](https://www.python.org/dev/peps/pep-0008/)
-* [Python 3 Computer Science Circles](http://cscircles.cemc.uwaterloo.ca/)
-* [Dive Into Python 3](http://www.diveintopython3.net/index.html)
-* [A Crash Course in Python for Scientists](http://nbviewer.jupyter.org/gist/anonymous/5924718)