human
Here's a good function header given the following:
I wrote the below code

    filename = os.path.join('CDAO/', source)
    def test_parse(self):
        trees = list(bp._io.parse(filename, 'cdao'))
    test_parse.__doc__ = ('Parse    the    phylogenies    in    %s.' % source)
    return test_parse

What's a good function header?
assistant
#Here's a good function header.

def _test_parse_factory(source):