It is all tied to naming in Python. Names are attached to objects in such a way that they can be detached and given to a new object. All objects without names are removed from memory (see here). Names available in your module are implemented as dictionaries and can be displayed using the __dict__ attribute (see here).
Type in
>>> import time >>> time.__dict__ The result is a dictionary containing the names used in defining objects in the built-in module time.