diff --git a/etg/_core.py b/etg/_core.py
index 04d47438..67acbdc7 100644
--- a/etg/_core.py
+++ b/etg/_core.py
@@ -291,7 +291,11 @@ def run():
             """)
 
 
-    module.addPyFunction('CallAfter', '(callableObj, *args, **kw)', doc="""\
+    module.addPyCode("""\
+            _T = TypeVar('_T')
+            _P = ParamSpec('_P')
+    """)
+    module.addPyFunction('CallAfter', '(callableObj: Callable[_P, _T], *args: _P.args, **kw: _P.kwargs) -> None', doc="""\
             Call the specified function after the current and pending event
             handlers have been completed.  This is also good for making GUI
             method calls from non-GUI threads.  Any extra positional or
@@ -322,7 +326,7 @@ def run():
             wx.PostEvent(app, evt)""")
 
 
-    module.addPyClass('CallLater', ['object'],
+    module.addPyClass('CallLater', ['Generic[_P, _T]'],
         doc="""\
             A convenience class for :class:`wx.Timer`, that calls the given callable
             object once after the given amount of milliseconds, passing any
@@ -342,7 +346,7 @@ def run():
             """,
         items = [
             PyCodeDef('__instances = {}'),
-            PyFunctionDef('__init__', '(self, millis, callableObj, *args, **kwargs)',
+            PyFunctionDef('__init__', '(self, millis, callableObj: Callable[_P, _T], *args: _P.args, **kwargs: _P.kwargs) -> None',
                 doc="""\
                     Constructs a new :class:`wx.CallLater` object.
 
@@ -366,7 +370,7 @@ def run():
 
             PyFunctionDef('__del__', '(self)', 'self.Stop()'),
 
-            PyFunctionDef('Start', '(self, millis=None, *args, **kwargs)',
+            PyFunctionDef('Start', '(self, millis: int | None=None, *args: _P.args, **kwargs: _P.kwargs) -> None',
                 doc="""\
                     (Re)start the timer
 
@@ -388,7 +392,7 @@ def run():
                     self.running = True"""),
             PyCodeDef('Restart = Start'),
 
-            PyFunctionDef('Stop', '(self)',
+            PyFunctionDef('Stop', '(self) -> None',
                 doc="Stop and destroy the timer.",
                 body="""\
                     if self in CallLater.__instances:
@@ -397,16 +401,16 @@ def run():
                         self.timer.Stop()
                         self.timer = None"""),
 
-            PyFunctionDef('GetInterval', '(self)', """\
+            PyFunctionDef('GetInterval', '(self) -> int', """\
                 if self.timer is not None:
                     return self.timer.GetInterval()
                 else:
                     return 0"""),
 
-            PyFunctionDef('IsRunning', '(self)',
+            PyFunctionDef('IsRunning', '(self) -> bool',
                 """return self.timer is not None and self.timer.IsRunning()"""),
 
-            PyFunctionDef('SetArgs', '(self, *args, **kwargs)',
+            PyFunctionDef('SetArgs', '(self, *args: _P.args, **kwargs: _P.kwargs) -> None',
                 doc="""\
                     (Re)set the args passed to the callable object.  This is
                     useful in conjunction with :meth:`Start` if
@@ -421,7 +425,7 @@ def run():
                     self.args = args
                     self.kwargs = kwargs"""),
 
-            PyFunctionDef('HasRun', '(self)', 'return self.hasRun',
+            PyFunctionDef('HasRun', '(self) -> bool', 'return self.hasRun',
                 doc="""\
                     Returns whether or not the callable has run.
 
@@ -429,7 +433,7 @@ def run():
 
                     """),
 
-            PyFunctionDef('GetResult', '(self)', 'return self.result',
+            PyFunctionDef('GetResult', '(self) -> _T', 'return self.result',
                 doc="""\
                     Returns the value of the callable.
 
@@ -437,7 +441,7 @@ def run():
                     :return: result from callable
                     """),
 
-            PyFunctionDef('Notify', '(self)',
+            PyFunctionDef('Notify', '(self) -> None',
                 doc="The timer has expired so call the callable.",
                 body="""\
                     if self.callable and getattr(self.callable, 'im_self', True):
@@ -456,7 +460,7 @@ def run():
     module.addPyCode("FutureCall = deprecated(CallLater, 'Use CallLater instead.')")
 
     module.addPyCode("""\
-        def GetDefaultPyEncoding():
+        def GetDefaultPyEncoding() -> str:
             return "utf-8"
         GetDefaultPyEncoding = deprecated(GetDefaultPyEncoding, msg="wxPython now always uses utf-8")
         """)
diff --git a/etgtools/pi_generator.py b/etgtools/pi_generator.py
index 1b3764a4..bac6d3ae 100644
--- a/etgtools/pi_generator.py
+++ b/etgtools/pi_generator.py
@@ -79,8 +79,9 @@ header_pyi = """\
 
 typing_imports = """\
 from __future__ import annotations
+from collections.abc import Callable
 from enum import IntEnum, IntFlag, auto
-from typing import Any, overload, TypeAlias
+from typing import Any, overload, TypeAlias, TypeVar, ParamSpec, Generic
 
 """
 
@@ -371,7 +372,7 @@ class PiWrapperGenerator(generators.WrapperGeneratorBase, FixWxPrefix):
         if pc.bases:
             stream.write('(%s):\n' % ', '.join(pc.bases))
         else:
-            stream.write('(object):\n')
+            stream.write(':\n')
         indent2 = indent + ' '*4
         if pc.briefDoc:
             stream.write('%s"""\n' % indent2)
@@ -465,8 +466,6 @@ class PiWrapperGenerator(generators.WrapperGeneratorBase, FixWxPrefix):
             bases = [self.fixWxPrefix(b, True) for b in bases]
             stream.write(', '.join(bases))
             stream.write(')')
-        else:
-            stream.write('(object)')
         stream.write(':\n')
         indent2 = indent + ' '*4