How to send from pyqt qdial value to arduino serial? How should be my code corrected?

Question

data=b''

data+=str(dial.value()).encode("utf-8")
#ser.write(b'hellr')
dial.setNotchesVisible(True)
dial.valueChanged.connect(spin.setValue)
#ser.write(spin.value())
#dial.valueChanged.connect(ser.write())