code: def unset_fields(self, fields):
          
  
          self.mongokat_collection.update_one({"_id": self["_id"]}, {"$unset": {
              f: 1 for f in fields
          }})
  
          for f in fields:
              if f in self:
                  del self[f]
docs: Removes this list of fields from both the local object and the DB.