def _extract_rev(self, line1, line2):
        def _extract(line):
            parts = line.split(None, 1)
            return parts[0], (len(parts) == 2 and parts[1] or None)

        try:
            if line1.startswith('--- ') and line2.startswith('+++ '):
                return _extract(line1[4:]), _extract(line2[4:])
        except (__HOLE__, IndexError):
            pass
        return (None, None), (None, None)
dataset/ETHPy150Open alex/django-vcs/django_vcs/diff.py/DiffRenderer._extract_rev