diff --git a/src/pyobo/api/metadata.py b/src/pyobo/api/metadata.py
index 9494c428..c49b4695 100644
--- a/src/pyobo/api/metadata.py
+++ b/src/pyobo/api/metadata.py
@@ -1,6 +1,7 @@
 """High-level API for metadata."""
 
 import logging
+from functools import lru_cache
 from typing import Any, cast
 
 from .utils import get_version
@@ -8,7 +9,6 @@
 from ..identifier_utils import wrap_norm_prefix
 from ..utils.cache import cached_json
 from ..utils.path import prefix_cache_join
-from functools import lru_cache
 
 __all__ = [
     "get_metadata",
diff --git a/src/pyobo/struct/typedef.py b/src/pyobo/struct/typedef.py
index a2b8af69..a9d3d1a2 100644
--- a/src/pyobo/struct/typedef.py
+++ b/src/pyobo/struct/typedef.py
@@ -21,7 +21,6 @@
     "example_of_usage",
     "from_species",
     "gene_product_member_of",
-    "get_reference_tuple",
     "has_dbxref",
     "has_gene_product",
     "has_homepage",