Welcome to Google's Python Class – a seven-segment, two-part free virtual class for people with a little bit of programming experience who want to learn Python. The class includes written materials, lecture videos, and lots of code exercises to practice Python coding. The first exercises work on basic Python concepts like strings and lists, building up to the later exercises which are full programs dealing with text files, processes, and http connections. The class is geared for people who have a little bit of programming experience in some language, enough to know what a "variable" or "if statement" is. Beyond that, you do not need to be an expert programmer to use this material.
Python is a dynamic, interpreted language. Source code does not declare the types of variables or parameters or methods. This makes the code short and flexible, and you lose the compile-time type checking in the source code. Python tracks the types of all values at runtime and flags code that does not make sense as it runs. (todo: link here to the companion video segment for this section)
To get started learning and using PHP for yourself, watch this wonderful lecture series from the Google Dev Team.