diff --git a/stdlib/3/string.pyi b/stdlib/3/string.pyi
index db437d95a..6427a76db 100644
--- a/stdlib/3/string.pyi
+++ b/stdlib/3/string.pyi
@@ -20,9 +20,9 @@ class Template:
     template: str
 
     def __init__(self, template: str) -> None: ...
-    def substitute(self, mapping: Mapping[str, str] = ..., **kwds: str) -> str: ...
-    def safe_substitute(self, mapping: Mapping[str, str] = ...,
-                        **kwds: str) -> str: ...
+    def substitute(self, mapping: Mapping[str, object] = ..., **kwds: object) -> str: ...
+    def safe_substitute(self, mapping: Mapping[str, object] = ...,
+                        **kwds: object) -> str: ...
 
 # TODO(MichalPokorny): This is probably badly and/or loosely typed.
 class Formatter: