diff --git a/mypy/stubgenc.py b/mypy/stubgenc.py
index ebb48c0640d2b..660ca31416a4a 100755
--- a/mypy/stubgenc.py
+++ b/mypy/stubgenc.py
@@ -307,10 +307,11 @@ def get_annotation(key: str) -> str | None:
         arglist: list[ArgSig] = []
 
         # Add the arguments to the signature
-        def add_args(args, get_default_value: Callable[[int, str], object | None]):
+        def add_args(args: list[str], get_default_value: Callable[[int, str], object | None]) -> None:
             for i, arg in enumerate(args):
                 # Check if the argument has a default value
-                if default_value := get_default_value(i, arg):
+                default_value = get_default_value(i, arg)
+                if default_value is not None:
                     if arg in annotations:
                         argtype = annotations[arg]
                     else:
@@ -325,7 +326,7 @@ def add_args(args, get_default_value: Callable[[int, str], object | None]):
                 else:
                     arglist.append(ArgSig(arg, get_annotation(arg), default=False))
 
-        def get_pos_default(i: int, _arg: str) -> object | None:
+        def get_pos_default(i: int, _arg: str) -> Any | None:
             if defaults and i >= len(args) - len(defaults):
                 return defaults[i - (len(args) - len(defaults))]
             else:
@@ -340,7 +341,7 @@ def get_pos_default(i: int, _arg: str) -> object | None:
         elif kwonlyargs:
             arglist.append(ArgSig("*"))
 
-        def get_kw_default(_i: int, arg: str) -> object | None:
+        def get_kw_default(_i: int, arg: str) -> Any | None:
             if kwonlydefaults:
                 return kwonlydefaults.get(arg)
             else:
diff --git a/mypy/test/teststubgen.py b/mypy/test/teststubgen.py
index bf2f814942501..71bbbc5d9420b 100644
--- a/mypy/test/teststubgen.py
+++ b/mypy/test/teststubgen.py
@@ -845,10 +845,9 @@ class TestClassVariableCls:
         assert_equal(gen.get_imports().splitlines(), ["from typing import ClassVar"])
         assert_equal(output, ["class C:", "    x: ClassVar[int] = ..."])
 
-
     def test_non_c_generate_signature_with_kw_only_args(self) -> None:
         class TestClass:
-            def test(self, arg0, *, keyword_only : str, keyword_only_with_default : int = 7):
+            def test(self, arg0: str, *, keyword_only: str, keyword_only_with_default: int = 7) -> None:
                 pass
 
         output: list[str] = []
@@ -869,7 +868,7 @@ def test(self, arg0, *, keyword_only : str, keyword_only_with_default : int = 7)
         assert_equal(
             output,
             [
-                "def test(self, arg0, *, keyword_only: str, keyword_only_with_default: int = ...): ..."
+                "def test(self, arg0: str, *, keyword_only: str, keyword_only_with_default: int = ...): ..."
             ],
         )