code: def _setPWMFrequency(self, pwm, device, message):
          
          value = self._CONFIG_PWM_TO_VALUE.get(pwm)
  
          if value is None:
              msg = "Invalid frequency: {}".format(pwm)
              self._log and self._log.error(msg)
              raise ValueError(msg)
  
          self._deviceConfig[device]['pwm'] = value
          return self._setConfig(self.PWM_PARAM, value, device, message)
docs: Set the PWM frequency.
  
          :Parameters:
            pwm : `int`
              The PWN frequency to set in hertz.
            device : `int`
              The device is the integer number of the hardware devices ID and
              is only used with the Pololu Protocol.
            message : `bool`
              If set to `True` a text message will be returned, if set to `False`
              the integer stored in the Qik will be returned.
  
          :Returns:
            A text message or an int. See the `message` parameter above.