code: func (d *DirectPinDriver) PwmWrite(level byte) (err error) {
  	if writer, ok := d.Connection().(PwmWriter); ok {
  		return writer.PwmWrite(d.Pin(), level)
  	}
  	err = ErrPwmWriteUnsupported
  	return
  }
docs: // PwmWrite writes the 0-254 value to the specified pin