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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 setTxPower(self, tx_power, peername=None):
 """Set the transmit power on one or all readers If peername is None, set the transmit power for all readers. Otherwise, set it for that specific reader. """

        if peername:
            protocols = [p for p in self.protocols
                         if p.peername[0] == peername]
        else:
            protocols = self.protocols
        for proto in protocols:
            proto.setTxPower(tx_power)