fix type annotation

app.py

@@ -18,7 +18,7 @@ def get_coordinates_from_mask(mask_in):
 
     return centroids
 
-def get_top_bottom_coordinates(coords: list[list[int,int]]) -> (list[int,int],list[int,int]):
+def get_top_bottom_coordinates(coords: list[list[int,int]]) -> tuple(list[int,int],list[int,int]):
     top_coord = min(coords, key=lambda x : x[1])
     bottom_coord = max(coords, key=lambda x : x[1])