Sets or clears the internal GPIO pull-up/down resistor.
        gpio:= 0-53.
         pud:= PUD_UP, PUD_DOWN, PUD_OFF.
        ...
        yield from pi.set_pull_up_down(17, apigpio.PUD_OFF)
        yield from pi.set_pull_up_down(23, apigpio.PUD_UP)
        yield from pi.set_pull_up_down(24, apigpio.PUD_DOWN)
        ...

def set_pull_up_down(self, gpio, pud):
        """
        Sets or clears the internal GPIO pull-up/down resistor.
        gpio:= 0-53.
         pud:= PUD_UP, PUD_DOWN, PUD_OFF.
        ...
        yield from pi.set_pull_up_down(17, apigpio.PUD_OFF)
        yield from pi.set_pull_up_down(23, apigpio.PUD_UP)
        yield from pi.set_pull_up_down(24, apigpio.PUD_DOWN)
        ...
        """
        res = yield from self._pigpio_aio_command(_PI_CMD_PUD, gpio, pud)
        return _u2i(res)