diff --git a/fgs/datatypes.py b/fgs/datatypes.py
index 3655ee82c7d68f359fc6459b42b9d3d1764bf6cd..68b9abcbcef17fe7ab885f68feb7733e518a4815 100644
--- a/fgs/datatypes.py
+++ b/fgs/datatypes.py
@@ -546,7 +546,7 @@ class Link:
             return self.url
     urlwithanchor = property(get_urlwithanchor, None, None)
 
-    def get_rel(self) -> str|None:
+    def get_rel(self):
         """
         Get the relation in the context of the rel html attribute for this link
         or None if no relation is known.