def hint(self, index):
        """Adds a 'hint', telling Mongo the proper index to use for the query.

        Judicious use of hints can greatly improve query
        performance. When doing a query on multiple fields (at least
        one of which is indexed) pass the indexed field as a hint to
        the query. Raises :class:`~pymongo.errors.OperationFailure` if the
        provided hint requires an index that does not exist on this collection,
        and raises :class:`~pymongo.errors.InvalidOperation` if this cursor has
        already been used.

        `index` should be an index as passed to
        :meth:`~pymongo.collection.Collection.create_index`
        (e.g. ``[('field', ASCENDING)]``) or the name of the index.
        If `index` is ``None`` any existing hint for this query is
        cleared. The last hint applied to this cursor takes precedence
        over all others.

        :Parameters:
          - `index`: index to hint on (as an index specifier)

        .. versionchanged:: 2.8
           The :meth:`~hint` method accepts the name of the index.
        """
        self.__check_okay_to_chain()
        self.__set_hint(index)
        return self
Adds a 'hint', telling Mongo the proper index to use for the query.

        Judicious use of hints can greatly improve query
        performance. When doing a query on multiple fields (at least
        one of which is indexed) pass the indexed field as a hint to
        the query. Raises :class:`~pymongo.errors.OperationFailure` if the
        provided hint requires an index that does not exist on this collection,
        and raises :class:`~pymongo.errors.InvalidOperation` if this cursor has
        already been used.

        `index` should be an index as passed to
        :meth:`~pymongo.collection.Collection.create_index`
        (e.g. ``[('field', ASCENDING)]``) or the name of the index.
        If `index` is ``None`` any existing hint for this query is
        cleared. The last hint applied to this cursor takes precedence
        over all others.

        :Parameters:
          - `index`: index to hint on (as an index specifier)

        .. versionchanged:: 2.8
           The :meth:`~hint` method accepts the name of the index.
        
stackoverflow/venv/lib/python3.6/site-packages/pymongo/cursor.py