to avoid accidentally exporting items that are not part of the API (such as
library modules which were imported and used within the module).
-The :keyword:`from` form with ``*`` may only occur in a module scope.
-Attempting to use it in class or function definitions will raise a
-:exc:`SyntaxError`.
-
-.. index:: single: __all__ (optional module attribute)
-
-The *public names* defined by a module are determined by checking the module's
-namespace for a variable named ``__all__``; if defined, it must be a sequence
-of strings which are names defined or imported by that module. The names
-given in ``__all__`` are all considered public and are required to exist. If
-``__all__`` is not defined, the set of public names includes all names found
-in the module's namespace which do not begin with an underscore character
-(``'_'``). ``__all__`` should contain the entire public API. It is intended
-to avoid accidentally exporting items that are not part of the API (such as
-library modules which were imported and used within the module).
-
The :keyword:`from` form with ``*`` may only occur in a module scope. The wild
card form of import --- ``import *`` --- is only allowed at the module level.
Attempting to use it in class or function definitions will raise a