Execute code located at the specified filesystem location.
path_name -- filesystem location of a Python script, zipfile,
or directory containing a top level __main__.py script.
Optional arguments:
init_globals -- dictionary used to pre-populate the module’s
globals dictionary before the code is executed.
run_name -- if not None, this will be used to set __name__;
otherwise, '<run_path>' will be used for __name__.
Returns the resulting module globals dictionary.
3.4: Updated to take advantage of the module spec feature added by PEP 451. This allows __cached__ to be set correctly in the case where __main__ is imported from a valid sys.path entry rather than being executed directly.
3.12: The setting of __cached__, __loader__, and __package__ are deprecated.
3.15: The global variable __cached__ is no longer set.