Group waste schedule events on the same day

Closes: #24

agenda/waste_schedule.py

@@ -1,6 +1,7 @@
 #!/usr/bin/python3
 
 import os
+from collections import defaultdict
 from datetime import date, datetime, timedelta
 
 import lxml.html
@@ -55,16 +56,19 @@ def parse_waste_schedule_date(day_and_month: str) -> date:
 
 def parse(root: lxml.html.HtmlElement) -> list[Event]:
     """Parse waste schedule."""
-    events = []
     tbody = root.find(".//table/tbody")
     assert tbody is not None
+    by_date = defaultdict(list)
     for e_service, e_next_date, e_following in tbody:
         assert e_service.text and e_next_date.text and e_following.text
         service = e_service.text
         next_date = parse_waste_schedule_date(e_next_date.text)
         following_date = parse_waste_schedule_date(e_following.text)
 
-        events.append(Event(name="waste_schedule", date=next_date, title=service))
-        events.append(Event(name="waste_schedule", date=following_date, title=service))
+        by_date[next_date].append(service)
+        by_date[following_date].append(service)
 
-    return events
+    return [
+        Event(name="waste_schedule", date=d, title=", ".join(services))
+        for d, services in by_date.items()
+    ]