code: def anticoll(self):
          
          back_data = []
          serial_number = []
  
          serial_number_check = 0
  
          self.dev_write(0x0D, 0x00)
          serial_number.append(self.act_anticl)
          serial_number.append(0x20)
  
          (error, back_data, back_bits) = self.card_write(self.mode_transrec, serial_number)
          if not error:
              if len(back_data) == 5:
                  for i in range(4):
                      serial_number_check = serial_number_check ^ back_data[i]
  
                  if serial_number_check != back_data[4]:
                      error = True
              else:
                  error = True
  
          return (error, back_data)
docs: Anti-collision detection.
          Returns tuple of (error state, tag ID).