code: func (a *AdafruitMotorHatDriver) SetServoMotorFreq(freq float64) (err error) {
  	if err = a.setPWMFreq(a.servoHatConnection, freq); err != nil {
  		return
  	}
  	return
  }
docs: // SetServoMotorFreq sets the frequency for the currently addressed PWM Servo HAT.