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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def read_raid(self, controller=None):
 """Get the current RAID configuration from the system. :param controller: If controller model its post-create read else post-delete :returns: current raid config. """

        if controller:
            if not self.logical_drives:
                msg = ('No logical drives found on the controller')
                LOG.debug(msg)
                raise exception.IloLogicalDriveNotFoundError(msg)
            raid_op = 'create_raid'
        else:
            raid_op = 'delete_raid'

        result, raid_message = self._check_smart_storage_message()

        if result:
            configured_raid_settings = self._conn.get(self.settings_uri)
            raid_data = {
                'logical_disks': self._generic_format(
                    configured_raid_settings.json(), controller=controller)}
            return raid_data
        else:
            if self.physical_drives is None or not raid_message:
                # This controller is not configured or controller
                # not used in raid operation
                return
            else:
                msg = ('Failed to perform the %(opr)s operation '
                       'successfully. Error - %(error)s'
                       % {'opr': raid_op, 'error': str(raid_message)})
                raise exception.IloError(msg)