code: def _FlushInput(self):
          
          self.ser.flush()
          flushed = 0
          while True:
              ready_r, ready_w, ready_x = select.select([self.ser], [],
                                                        [self.ser], 0)
              if len(ready_x) > 0:
                  logging.error("Exception from serial port.")
                  return None
              elif len(ready_r) > 0:
                  flushed += 1
                  self.ser.read(1)  # This may cause underlying buffering.
                  self.ser.flush()  # Flush the underlying buffer too.
              else:
                  break
docs: Flush all read data until no more available.