def test_docstringIsMerged(self):
        """
        Merging C{foo} into C{bar} returns a function with C{foo}'s docstring.
        """

        def foo():
            """
            This is foo.
            """

        def bar():
            """
            This is bar.
            """

        baz = util.mergeFunctionMetadata(foo, bar)
        self.assertEqual(baz.__doc__, foo.__doc__)

        Merging C{foo} into C{bar} returns a function with C{foo}'s docstring.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/test/test_util.py