<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _set_address(self, address, force=None):
 """ Set i2c slave address to use for subsequent calls. :param address: :type address: int :param force: :type force: Boolean """

        force = force if force is not None else self.force
        if self.address != address or self._force_last != force:
            if force is True:
                ioctl(self.fd, I2C_SLAVE_FORCE, address)
            else:
                ioctl(self.fd, I2C_SLAVE, address)
            self.address = address
            self._force_last = force