diff --git a/sphinx/domains/python.py b/sphinx/domains/python.py
index 48370d6c7..0ca851669 100644
--- a/sphinx/domains/python.py
+++ b/sphinx/domains/python.py
@@ -482,10 +482,7 @@ class PyObject(ObjectDescription[Tuple[str, str]]):
 
         sig_prefix = self.get_signature_prefix(sig)
         if sig_prefix:
-            if isinstance(sig_prefix, str):
-                signode += addnodes.desc_annotation(sig_prefix, sig_prefix)
-            else:
-                signode += addnodes.desc_annotation(str(sig_prefix), '', *sig_prefix)
+            signode += addnodes.desc_annotation(str(sig_prefix), '', *sig_prefix)
 
         if prefix:
             signode += addnodes.desc_addname(prefix, prefix)