code: def track(*fields):
      
      def inner(cls):
          _track_class(cls, fields)
          _add_get_tracking_url(cls)
          return cls
      return inner
docs: Decorator used to track changes on Model's fields.
  
         :Example:
         >>> @track('name')
         ... class Human(models.Model):
         ...     name = models.CharField(max_length=30)