adding persistence

lib/DataStore.py

@@ -0,0 +1,29 @@
+from pathlib import Path
+from .TimeSlot import TimeSlot
+import json
+
+
+class DataStore:
+    def __init__(self, filename: Path, create=False):
+        self._filename = filename
+        if create:
+            self._time_slots = []
+            self._write_update()
+        else:
+            with open(self._filename, "r") as f:
+                self._time_slots = list(json.load(f))
+
+    def _write_update(self):
+        with open(self._filename, "w+") as f:
+            json.dump(self._time_slots, f, default=vars)
+
+    def add_time_slot(self, time_slot: TimeSlot):
+        self._time_slots.append(time_slot)
+        self._write_update()
+
+    def remove_time_slot(self, time_slot: TimeSlot):
+        self._time_slots.remove(time_slot)
+        self._write_update()
+
+    def get_all_time_slots(self):
+        return self._time_slots[:]