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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def send_ping(self, payload=''):
 """ Send a PING control frame with an optional payload. """

        self.send_frame(ControlFrame(OPCODE_PING, payload),
                        lambda: self.onping(payload))
        self.ping_payload = payload
        self.ping_sent = True