What are docstrings and how do I use them to improve my code readability?

Docstrings are strings placed at the beginning of classes, functions, or .py files. They are implemented using three single quotes at the beginning and end. For example:

def Addition(a,b):

''' This function adds a and b together. '''

    return a+b

This docstring is then accessed in the interpreter using "Addition.doc"(no quotes). Docstrings are used to document how to use the class, function or script that it refers to, and so can improve code readability and maintainability.