diff --git a/src/maggma/stores/mongolike.py b/src/maggma/stores/mongolike.py
index 60d96533a..d4b6e4033 100644
--- a/src/maggma/stores/mongolike.py
+++ b/src/maggma/stores/mongolike.py
@@ -121,7 +121,7 @@ def distinct(
                 d["_id"]
                 for d in self._collection.aggregate([{"$group": {"_id": f"${field}"}}])
             ]
-            if all(isinstance(d, list) for d in filter(None, distinct_vals)):
+            if all(isinstance(d, list) for d in filter(None, distinct_vals)):  # type: ignore
                 distinct_vals = list(chain.from_iterable(filter(None, distinct_vals)))
 
         return distinct_vals if distinct_vals is not None else []