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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 unicast(self, socket_id, event, data):
 """Sends an event to a single socket. Returns `True` if that worked or `False` if not. """

        payload = self._server.serialize_event(event, data)
        rv = self._server.sockets.get(socket_id)
        if rv is not None:
            rv.socket.send(payload)
            return True
        return False