def save(self, filename=None):
        filename = Path(filename) if filename is not None else self.filename
        with filename.open("w") as f:
            f.write(self.yaml)
def __init__(self, root, cwd, badfn=None, rules=[]):
        super(treematcher, self).__init__(root, cwd, badfn)
        rules = list(rules)
        self._matcher = pathmatcher.treematcher(rules)
        self._rules = rules