diff --git a/spacy/kb/kb.pyx b/spacy/kb/kb.pyx
index 15dec075d..dcd7ae189 100644
--- a/spacy/kb/kb.pyx
+++ b/spacy/kb/kb.pyx
@@ -36,7 +36,7 @@ cdef class KnowledgeBase:
         entity's embedding vector. Depending on the KB implementation, further properties - such as the prior
         probability of the specified mention text resolving to that entity - might be included.
         If no candidates are found for a given mention, an empty list is returned.
-        mentions (Iterable[SpanGroup]): Mentions for which to get candidates.
+        mentions (Iterator[SpanGroup]): Mentions for which to get candidates.
         RETURNS (Iterator[Iterable[Iterable[Candidate]]]): Identified candidates.
         """
         raise NotImplementedError(