adding definition for timespans for ls and acc command

util/timeslotlist.py

@@ -0,0 +1,12 @@
+import re
+from datetime import timedelta
+
+from model.TimeSlot import TimeSlot
+
+
+def accumulate_duration(timeslots: list[TimeSlot]) -> timedelta:
+    return sum([ts.duration() for ts in timeslots], start=timedelta(0))
+
+def filter(timeslots: list[TimeSlot], query: str) -> list[TimeSlot]:
+    pattern = re.compile(query)
+    return [ts for ts in timeslots if pattern.search(ts.name)]