>>> import inspect
>>> import types
... custom_module = types.ModuleType('my_custom_module')
... 
>>> inspect.getfile(custom_module)
Traceback (most recent call last):
 File "<python-input-2>", line 1, in <module>
 inspect.getfile(custom_module)
 ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^
 File "/Users/yihong/repos/cpython/Lib/inspect.py", line 822, in getfile
 raise TypeError('{!r} is a built-in module'.format(object))
TypeError: <module 'my_custom_module'> is a built-in module