human
Solve the following python programming problem given the following code:
@ base.remotable 
def save(self, expected_vm_state = None, expected_task_state = None, admin_state_reset = False) : 
    'Save updates to this instance

        Column-wise updates will be made based on the result of
        self.what_changed(). If expected_task_state is provided,
        it will be checked against the in-database copy of the
        instance before updates are made.

        :param:context: Security context
        :param:expected_task_state: Optional tuple of valid task states
        for the instance to be in
        :param:expected_vm_state: Optional tuple of valid vm states
        for the instance to be in
        :param admin_state_reset: True if admin API is forcing setting
        of task_state/vm_state

        ' 
    self._sync_cells = (not self._cell_name_blocks_sync ()) 
    context = self._context 
    cell_type = cells_opts.get_cell_type () 
    if (cell_type is not None) : 
        stale_instance = self.obj_clone () 
cells_update_from_api = ((cell_type == 'api') and self.cell_name and self._sync_cells) 
    if cells_update_from_api : 
        def _handle_cell_update_from_api() : 
            cells_api = cells_rpcapi.CellsAPI () 
            cells_api.instance_update_from_api (context, stale_instance, expected_vm_state, expected_task_state, admin_state_reset) 
updates = { 
        
} 
    changes = self.obj_what_changed () 
    for field in self.fields : 
        if (self.obj_attr_is_set (field) and isinstance (self.fields [field], fields.ObjectField)) : 
            try : 
                getattr (self, ('_save_%s' % field)) (context) 
except AttributeError : 
                LOG.exception (_LE ('No save handler for %s'), field, instance = self) 
except db_exc.DBReferenceError as exp : 
                if (exp.key != 'instance_uuid') : 
                    raise 
raise exception.InstanceNotFound (instance_id = self.uuid) 
else : 
            if (field in changes) : 
                if ((field == 'cell_name') and (self [field] is not None) and self [field].startswith...

    
    

    Fix the buggy line: expected_attrs = [expected_vm_state for attr in _INSTANCE_OPTIONAL_JOINED_FIELDS if self.obj_attr_is_set (attr)]
assistant
#Here is Python program to fix the buggy line: expected_attrs = [expected_vm_state for attr in _INSTANCE_OPTIONAL_JOINED_FIELDS if self.

expected_attrs = [attr for attr in _INSTANCE_OPTIONAL_JOINED_FIELDS if self.obj_attr_is_set (attr)]