Update app.py

app.py

@@ -136,7 +136,7 @@ class Echo(torchvision.datasets.VisionDataset):
             self.frames = collections.defaultdict(list)
             self.trace = collections.defaultdict(_defaultdict_of_lists)
 
-            with open(f"{self.root}VolumeTracings.csv")) as f:
+            with open(f"{self.root}VolumeTracings.csv") as f:
                 header = f.readline().strip().split(",")
                 assert header == ["FileName", "X1", "Y1", "X2", "Y2", "Frame"]