Reimplement selected_from based on Receiver.triggered

Signed-off-by: Sahas Subramanian <[email protected]>

Author: shsms

src/frequenz/channels/_select.py

@@ -269,9 +269,7 @@ def selected_from(
     Returns:
         Whether the given receiver was selected.
     """
-    if handled := selected._recv is receiver:  # pylint: disable=protected-access
-        selected._handled = True  # pylint: disable=protected-access
-    return handled
+    return receiver.triggered(selected)
 
 
 class SelectError(Error):
@@ -378,7 +376,7 @@ async def select(  # noqa: DOC503
         import datetime
         from typing import assert_never
 
-        from frequenz.channels import ReceiverStoppedError, select, selected_from
+        from frequenz.channels import ReceiverStoppedError, select
         from frequenz.channels.timer import SkipMissedAndDrift, Timer, TriggerAllMissed
 
         timer1 = Timer(datetime.timedelta(seconds=1), TriggerAllMissed())