adding these print statements, we can check if the landmarks are being correctly extracted and if the number of landmarks is as expected for each category

app.py

@@ -95,6 +95,11 @@ def extract_landmarks(frame):
     face_landmarks = face_results.multi_face_landmarks[0]
     lip_landmarks = [face_landmarks.landmark[i] for i in LIPS_IDXS0 - START_IDX]
 
+    print(f"Number of landmarks for hand1: {len(hand1_landmarks.landmark)}")
+    print(f"Number of landmarks for hand2: {len(hand2_landmarks.landmark)}")
+    print(f"Number of landmarks for pose: {len(pose_landmarks.landmark)}")
+    print(f"Number of landmarks for lip: {len(lip_landmarks)}")
+
     return hand1_landmarks, hand2_landmarks, pose_landmarks, lip_landmarks