django与ajax喜欢和不同

I , so I wrote an application with django and implemented a like and unlike function but I noticed that it works fine but the problem is if a user likes a post and decides to unlike it , the likes . count would go to -1 instead of 0 and thus it is possible for a two users like to become 3 but if one of the two unlikes it then it goes to 1 . below is my jQuery function I , so I wrote an application with django and i