Add a basic python example for variable scope

Python/045_scope.py

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+# Scope of variables
+# The "scope" of a variable means:
+#    "where is this variable and its value accessible"
+
+# Variables are used to store data throughout a program.
+# Creating a variable is commonly done like this:
+#
+# A string literal:
+#    my_string = "This Is Text"
+# A scalar value:
+#    my_number = 47
+# A data structure (i.e. list, dict, tuple, set, etc.):
+#    my_list = ["a", "j", "p", "y"]
+# An object/class instantiation:
+#    my_object = Button("label", color=(25, 128, 199))
+#
+# Each of the examples above are "variable assignments".
+# An assignment names a variable (such as 'my_number' above)
+# and sets a specific value to that named variable.
+
+# Variables assigned at the "top logical level" of the program
+# are in what we call the "global scope" or called "global variables".
+# This means that those variables and their values are available
+# within the main body of the program, from within functions,
+# and from within classes.
+#
+# More informationL https://www.w3schools.com/python/python_variables_global.asp
+# Better/More Complex: https://realpython.com/python-use-global-variable-in-function/
+
+name = "Donkey"
+age = 44
+streets = ["Brown Bark", "Pine Knot", "Thomas Jefferson"]
+
+def alter():
+    print(name)
+    age = 3
+    streets[1] = "George Wythe"
+
+alter()
+print(name)
+print(age)
+print(streets)
+
+# This shows us several things:
+#    1) The variable "name" is available inside the alter() function
+#    2) The streets[] list is available
+#    3) and its elements can be changed within the alter() function
+#    4) The "age" variable assigned in the alter() function does not
+#       effect the globally scoped variable "age"
+#
+# One of the key topics here is "mutability". This topic is quite
+# complex and involved. Here's a link where you can read more:
+# https://realpython.com/python-mutable-vs-immutable-types/
+#
+# The TLDR of that page is:
+#    1) It's poor practice to try to change any global scope variables inside a function
+#    2) Variable types that are "mutable" (link above) can be altered in subroutines/functions
+#    3) Variable types that are "immutable" (link above) CANNOT be altered in subs/functions