':returns: Whether the returned close code is a valid hybi return code.'

def _is_valid_close_code(self, code):

    if (code < 1000):
        return False
    if (1004 <= code <= 1006):
        return False
    if (1012 <= code <= 1016):
        return False
    if (code == 1100):
        return False
    if (2000 <= code <= 2999):
        return False
    return True
