There are various naming conventions used in Python programs.
PEP 0008 specifies naming conventions for class names (e.g. GenericTree), package and module names (e.g. generictree and generic_tree), function and variable names (storestate or store_state; mixedCase is dispreferred), and more. Google Python Style Guide follows similar naming conventions.
The above stands in contrast to Java naming convention (e.g. storeState for method names) and C# naming convention (e.g. StoreState for method names).
In Python 2, the standard library contains multiple deviations from PEP 0008. For instance, Tkinter module is spelled as Tkinter with capital T; this was renamed to tkinter in Python 3.