Update usage_tracker.py

usage_tracker.py

@@ -1,6 +1,12 @@
+# usage_tracker.py
+
 from collections import Counter
 
 
+# =====================================================
+# BUILD USAGE MAP
+# =====================================================
+
 def build_usage_map(
     timeline
 ):
@@ -13,4 +19,41 @@ def build_usage_map(
             scene["path"]
         ] += 1
 
-    return dict(usage)
+    return dict(usage)
+
+
+# =====================================================
+# DECREASE USAGE
+# =====================================================
+
+def consume_scene(
+    usage_map,
+    scene
+):
+
+    path = scene["path"]
+
+    if path not in usage_map:
+        return False
+
+    usage_map[path] -= 1
+
+    return usage_map[path] <= 0
+
+
+# =====================================================
+# STATS
+# =====================================================
+
+def remaining_files(
+    usage_map
+):
+
+    count = 0
+
+    for value in usage_map.values():
+
+        if value > 0:
+            count += 1
+
+    return count