'send close data to the server.
status: status code to send. see STATUS_XXX.
reason: the reason to close. This must be string or bytes.'

def send_close(self, status=STATUS_NORMAL, reason=six.b('')):

    if ((status < 0) or (status >= ABNF.LENGTH_16)):
        raise ValueError('code    is    invalid    range')
    self.connected = False
    self.send((struct.pack('!H', status) + reason), ABNF.OPCODE_CLOSE)
