Clean up section about types, add aside on duck typing
Add an aside about comments in Python
Add an explanation of what it means to be a double-precision float
Add text describing why comments are good ideas
Update the section on variables and immutability, add duck-typing and variable name examples
Clean up section on lists, add a few examples
Clean up section on tuples and add an example for why they exist
Add an example illustrating the mutability of lists
Clarify the ordering and indexing of tuples
Clean up and add examples to the dictionary section