code: def read(self, gpio):
          
          res = yield from self._pigpio_aio_command(_PI_CMD_READ, gpio, 0)
          return _u2i(res)
docs: Returns the GPIO level.
          gpio:= 0-53.
          ...
          yield from pi.set_mode(23, pigpio.INPUT)
          yield from pi.set_pull_up_down(23, pigpio.PUD_DOWN)
          print(yield from pi.read(23))
          0
          yield from pi.set_pull_up_down(23, pigpio.PUD_UP)
          print(yield from pi.read(23))
          1
          ...