Get index and doctype args.

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