diff --git a/stdlib/3/ast.pyi b/stdlib/3/ast.pyi
index 11417d068..56d4dc134 100644
--- a/stdlib/3/ast.pyi
+++ b/stdlib/3/ast.pyi
@@ -184,7 +184,10 @@ if sys.version_info >= (3, 9):
     def unparse(ast_obj: AST) -> str: ...
 
 def copy_location(new_node: _T, old_node: AST) -> _T: ...
-def dump(node: AST, annotate_fields: bool = ..., include_attributes: bool = ...) -> str: ...
+if sys.version_info >= (3, 9):
+    def dump(node: AST, annotate_fields: bool = ..., include_attributes: bool = ..., *, indent: Union[int, str, None] = ...) -> str: ...
+else:
+    def dump(node: AST, annotate_fields: bool = ..., include_attributes: bool = ...) -> str: ...
 def fix_missing_locations(node: _T) -> _T: ...
 def get_docstring(node: AST, clean: bool = ...) -> str: ...
 def increment_lineno(node: _T, n: int = ...) -> _T: ...