Style Guide for Python Code

I love Python; the style guide is a great resource for writing consistent looking code. I particularly enjoyed these:

Always use self for the first argument to instance methods.
_single_leading_underscore: weak “internal use” indicator. E.g. from M import * does not import objects whose name starts with an underscore.
single_trailing_underscore_: used by convention to avoid conflicts with Python keyword
__double_leading_underscore: when naming a class attribute, invokes name mangling (inside class FooBar, __boo becomes _FooBar__boo).
Comparisons to singletons like None should always be done with is or is not, never the equality operators.