new_contents: #soil moisture sensor.
  #VCC, GND, AO, DO
  #DO <--> GPIO
  #AO <--> ADC Port
  #if value is low than defined data, DO value is 0, 
  #if value is high than defined data, DO value is 1.
  #AO is the specific value.
  from pyb import Pin
  p_in = Pin('Y12', Pin.IN, Pin.PULL_UP)
  p_in.value
  
  
  adc = pyb.ADC(Pin('Y11'))       # create an analog object from a pin
  adc = pyb.ADC(pyb.Pin.board.Y11)
  val = adc.read()                # read an analog value
  
subject: Create soil_moisture.py