def parent(prnt_doc, child_doc):
    """ Wherever the docstring for a child-class' attribute (or for the class itself) is
    `None`, inherit the corresponding docstring from the parent.

    *NOTE* As of Python 3.5, this is the default behavior of the built-in function
    inspect.getdoc, and thus this style is deprecated Python 3.(>=5). """
    return child_doc if child_doc is not None else prnt_doc
