error in outer indentation level for IoT device Distance sensor

we are student from college doing our project which is inter and outer counter that count the student who inter the room and leave it and theres problem in line 30 says theres outer indentation and also theres trackback error, so we have two sensor ( sensor1 , sensor2) when sensor1 calculate the distance then sensor2 it means the person is entering and the opposite , also we don't have any idea about indentation