django exception Object of type ‘User’ is not JSON serializable?

I’m getting the error mentioned in the title of this question. Here i’m wokring with django only. Not using django restframework. The point is i want to query user with a json response from the user model. How can i do that ?

class ProfileManager(models.Manager):
    def toggle_follow(self, request_user,user_id, username_to_toggle,json_follower):
        profile_ = UserProfile.objects.get(user__username__iexact=request_user.username)
        is_following = False
        follower = profile_.follower.filter(username__iexact=username_to_toggle).first()
        
        if follower:
            profile_.follower.remove(follower.id)
            actor = User.objects.get(pk=user_id)
            user = User.objects.get(username=username_to_toggle)
            json_follower = user
        else:
            new_follower = User.objects.get(username__iexact=username_to_toggle)
            profile_.follower.add(new_follower.id)
            actor = User.objects.get(pk=user_id)
            user = User.objects.get(username=username_to_toggle)
            notify.send(actor, recipient=user, verb='follow you')
            json_follower = new_follower
            is_following = True
        return profile_, is_following,json_follower