move timer callback param

docs/examples/timers/clock.py

@@ -7,15 +7,16 @@ from textual.widget import Widget
 
 
 class Clock(Widget):
-    async def on_mount(self, event):
-        self.set_interval(1, callback=self.refresh)
+    def on_mount(self):
+        self.set_interval(1, self.refresh)
 
-    def render(self) -> Align:
-        time = datetime.now().strftime("%X")
+    def render(self):
+        time = datetime.now().strftime("%c")
         return Align.center(time, vertical="middle")
 
+
 class ClockApp(App):
-    async def on_mount(self, event):
+    async def on_mount(self):
         await self.view.dock(Clock())
 
 

src/textual/message_pump.py

@@ -15,8 +15,6 @@ from ._timer import Timer, TimerCallback
 from ._callback import invoke
 from ._context import active_app
 from .message import Message
-from .reactive import Reactive
-
 
 if TYPE_CHECKING:
     from .app import App
@@ -126,9 +124,9 @@ class MessagePump:
     def set_timer(
         self,
         delay: float,
+        callback: TimerCallback = None,
         *,
         name: str | None = None,
-        callback: TimerCallback = None,
     ) -> Timer:
         timer = Timer(self, delay, self, name=name, callback=callback, repeat=0)
         timer_task = asyncio.get_event_loop().create_task(timer.run())
@@ -138,9 +136,9 @@ class MessagePump:
     def set_interval(
         self,
         interval: float,
+        callback: TimerCallback = None,
         *,
         name: str | None = None,
-        callback: TimerCallback = None,
         repeat: int = 0,
     ):
         timer = Timer(