def _index_command(self, type, columns, index):
        if not isinstance(columns, list):
            columns = [columns]

        if not index:
            index = self._create_index_name(type, columns)

        return self._add_command(type, index=index, columns=columns)
Add a new index command to the blueprint.
dataset/ETHPy150Open sdispater/orator/orator/schema/blueprint.py/Blueprint._index_command