chore(session): Return Pane type for attached_pane

Author: tony

libtmux/session.py

@@ -18,6 +18,7 @@
     has_version,
     session_check_name,
 )
+from .pane import Pane
 from .window import Window
 
 logger = logging.getLogger(__name__)
@@ -366,7 +367,7 @@ def select_window(self, target_window: str) -> Window:
         return self.attached_window
 
     @property
-    def attached_pane(self):
+    def attached_pane(self) -> t.Optional[Pane]:
         """Return active :class:`Pane` object."""
 
         return self.attached_window.attached_pane