add accumulation of captured time

main.py

@@ -1,6 +1,6 @@
 #!/usr/bin/python3
 
-from util.str_to_datetime import datetime
+from util.str_to_datetime import str_to_datetime as datetime
 
 from model.TimeSlotContainer import time_slot_container as tsc
 from model.TimeSlot import TimeSlot
@@ -35,3 +35,7 @@ if __name__ == "__main__":
 
     elif args.command == "add":
         tsc.add_time_slot(args.name, datetime(args.start), datetime(args.end))
+
+    elif args.command == "acc":
+        d = tsc.accumulate_duration(args.query)
+        print(f"{d.seconds // 3600}:{d.seconds % 3600 // 60}")