diff --git a/api/python/src/cellxgene_ontology_guide/ontology_parser.py b/api/python/src/cellxgene_ontology_guide/ontology_parser.py
index 554522e..2b6a69e 100644
--- a/api/python/src/cellxgene_ontology_guide/ontology_parser.py
+++ b/api/python/src/cellxgene_ontology_guide/ontology_parser.py
@@ -1,7 +1,7 @@
 import re
 from typing import Any, Dict, Iterable, List, Union
 
-from cellxgene_ontology_guide.constants import VALID_NON_ONTOLOGY_TERMS
+from cellxgene_ontology_guide._constants import VALID_NON_ONTOLOGY_TERMS
 from cellxgene_ontology_guide.entities import Ontology
 from cellxgene_ontology_guide.supported_versions import CXGSchema