Clears gpios 0-31 if the corresponding bit in bits is set.

        bits:= a 32 bit mask with 1 set if the corresponding gpio is
             to be cleared.

        A returned status of PI_SOME_PERMITTED indicates that the user
        is not allowed to write to one or more of the gpios.

        ...
        pi.clear_bank_1(int("111110010000",2))
        ...

def clear_bank_1(self, bits):
        """
        Clears gpios 0-31 if the corresponding bit in bits is set.

        bits:= a 32 bit mask with 1 set if the corresponding gpio is
             to be cleared.

        A returned status of PI_SOME_PERMITTED indicates that the user
        is not allowed to write to one or more of the gpios.

        ...
        pi.clear_bank_1(int("111110010000",2))
        ...
        """
        res = yield from self._pigpio_aio_command(_PI_CMD_BC1, bits, 0)
        return _u2i(res)