Add pragma: no branch in middleware/exceptions.py

Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com>

starlette/middleware/exceptions.py

@@ -28,7 +28,7 @@ def __init__(
             HTTPException: self.http_exception,
             WebSocketException: self.websocket_exception,
         }
-        if handlers is not None:
+        if handlers is not None:  # pragma: no branch
             for key, value in handlers.items():
                 self.add_exception_handler(key, value)