def clear(self):
        super(GroupedRequirements, self).clear()
        self.create_default_groups()
def __init__(self, root, cwd, files, badfn=None):
        super(exactmatcher, self).__init__(root, cwd, badfn)

        if isinstance(files, list):
            self._files = files
        else:
            self._files = list(files)