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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 select(self, cb=None):
        '''
        Set this channel to use transactions.
        '''
        if not self._enabled:
            self._enabled = True
            self.send_frame(MethodFrame(self.channel_id, 90, 10))
            self._select_cb.append(cb)
            self.channel.add_synchronous_cb(self._recv_select_ok)