i01 = Runtime.start("i01", "InMoov")
hand = i01.startRightHand("COM15")
arduino = Runtime.getService("i01.right")

keepHorizontalOutPin = 13
keepHorizontal = False

def keepHorizontalStart():
  global keepHorizontal
  arduino.digitalWrite(keepHorizontalOutPin, 1)
  keepHorizontal = True
  i01.rightHand.wrist.detach()
  
def keepHorizontalStop():
  global keepHorizontal
  arduino.digitalWrite(keepHorizontalOutPin, 0)
  keepHorizontal = False
  i01.rightHand.wrist.attach()
  
// then you can just call the keepHorizontalStart() and keepHorizontalStop() in python