human
Solve the following python programming problem given the following code:
def at_traverse(self, traversing_object, target_location) : 
    '
        Implements the actual traversal, using utils.delay to delay the move_to.
        ' 
    move_speed = (traversing_object.db.move_speed or 'walk') 
    move_delay = MOVE_DELAY.get (move_speed, 4) 
    def move_callback() : 
        'This callback will be called by utils.delay after move_delay seconds.' 
        source_location = traversing_object.location 
        if traversing_object.move_to (target_location) : 
            self.at_after_traverse (traversing_object, source_location) 
else : 
            if self.db.err_traverse : 
                self.caller.msg (self.db.err_traverse) 
else : 
                self.at_failed_traverse (traversing_object) 
traversing_object.msg (('You start moving %s at a %s.' % (self.key, move_speed))) 
    deferred = utils.delay (move_delay, callback = move_callback) 
    traversing_object.ndb.currently_moving = move_callback 

    
    

    Fix the buggy line: traversing_object.ndb.currently_moving = move_callback
assistant
#Here is Python program to fix the buggy line: traversing_object.

traversing_object.ndb.currently_moving = deferred