docs: def add_py_file(self, src, dest=None):
          """This is a special case of :py:meth:`add_file` that helps for adding
          a ``py`` when a ``pyc`` may be present as well. So for example, if
          ``__file__`` is ``foo.pyc`` and you do:
  
          .. code-block:: python
  
            archive.add_py_file(__file__)
  
          then this method will add ``foo.py`` instead if it exists, and raise
          ``IOError`` if it doesn't.
  
          """
          src = src[:-1] if src.endswith('.pyc') else src
          self.add_file(src, dest)