mypy: Improve mouse_event signatures based on urwid docs.

Author: neiljp

zulipterminal/ui_tools/boxes.py

@@ -646,8 +646,8 @@ def selectable(self) -> bool:
         # is designed to take focus.
         return True
 
-    def mouse_event(self, size: urwid_Size, event: Any, button: Any,
-                    col: int, row: int, focus: int) -> Union[bool, Any]:
+    def mouse_event(self, size: urwid_Size, event: str, button: int,
+                    col: int, row: int, focus: bool) -> bool:
         if event == 'mouse press':
             if button == 1:
                 self.keypress(size, 'enter')

zulipterminal/ui_tools/views.py

@@ -132,7 +132,7 @@ def load_new_messages(self, anchor: int) -> None:
         self.new_loading = False
 
     def mouse_event(self, size: urwid_Size, event: str, button: int, col: int,
-                    row: int, focus: Any) -> Any:
+                    row: int, focus: bool) -> bool:
         if event == 'mouse press':
             if button == 4:
                 self.keypress(size, 'up')
@@ -280,7 +280,7 @@ def update_streams(self, search_box: Any, new_text: str) -> None:
             self.view.controller.update_screen()
 
     def mouse_event(self, size: urwid_Size, event: str, button: int, col: int,
-                    row: int, focus: Any) -> Any:
+                    row: int, focus: bool) -> bool:
         if event == 'mouse press':
             if button == 4:
                 self.keypress(size, 'up')
@@ -367,7 +367,7 @@ def update_topics_list(self, stream_id: int, topic_name: str,
             self.list_box.set_focus(0)
 
     def mouse_event(self, size: urwid_Size, event: str, button: int, col: int,
-                    row: int, focus: Any) -> Any:
+                    row: int, focus: bool) -> bool:
         if event == 'mouse press':
             if button == 4:
                 self.keypress(size, 'up')
@@ -406,7 +406,7 @@ def __init__(self, users_btn_list: List[Any]) -> None:
         super().__init__(self.log)
 
     def mouse_event(self, size: urwid_Size, event: str, button: int, col: int,
-                    row: int, focus: Any) -> Any:
+                    row: int, focus: bool) -> bool:
         if event == 'mouse press':
             if button == 4:
                 for _ in range(5):