docs: def get_direct_fields_from_model(model_class):
      """ Direct, not m2m, not FK """
      direct_fields = []
      all_fields_names = _get_all_field_names(model_class)
      for field_name in all_fields_names:
          field, model, direct, m2m = _get_field_by_name(model_class, field_name)
          if direct and not m2m and not _get_remote_field(field):
              direct_fields += [field]
      return direct_fields