'Added \'hint\' support, 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.
Hinting will not do anything if the corresponding index does not exist.
The last hint applied to this cursor takes precedence over all others.
.. versionadded:: 0.5'

def hint(self, index=None):

    queryset = self.clone()
    queryset._hint = index
    if queryset._cursor_obj:
        queryset._cursor_obj.hint(queryset._hint)
    return queryset
