Helper to provide extensibility for pickle/cPickle.
 
This is only useful to add pickle support for extension types defined in
C, not for instances of user-defined classes.

Functions
		__newobj__(cls, *args) add_extension(module, name, code) Register an extension code. clear_extension_cache() constructor(object) pickle(ob_type, pickle_function, constructor_ob=None) remove_extension(module, name, code) Unregister an extension code.  For testing only.

Data
		__all__ = ['pickle', 'constructor', 'add_extension', 'remove_extension', 'clear_extension_cache']