docs: def _es_args(self, resource, refresh=None, source_projections=None):
          """Get index and doctype args."""
          datasource = self.get_datasource(resource)
          args = {
              'index': self._resource_index(resource),
              'doc_type': datasource[0],
          }
          if source_projections:
              args['_source'] = source_projections
          if refresh:
              args['refresh'] = refresh
  
          return args