def __init__(self, name, host='127.0.0.1', port=27017):
        self.name = name
        self.host = host
        self.port = port
def _split(self, path):
        if "/" in path:
            subdir, rest = path.split("/", 1)
        else:
            subdir, rest = path, ""
        if not subdir:
            raise error.ProgrammingError("path cannot be absolute")
        return subdir, rest