code: def hdel(self, *args):
          
          if args and not any(arg in self._instancehash_fields for arg in args):
              raise ValueError("Only InstanceHashField can be used here.")
  
          # Set indexes for indexable fields.
          for field_name in args:
              field = self.get_field(field_name)
              if field.indexable:
                  field.deindex()
  
          # Return the number of fields really deleted
          return self._call_command('hdel', *args)
docs: This command on the model allow deleting many instancehash fields with
          only one redis call. You must pass hash names to retrieve as arguments