Merge pull request #385 from City-of-Turku/fix/eco-counter-handle-err…

…oneous-weeks-in-data-migration-0024

Fix/eco counter handle erroneous weeks in data migration 0024

eco_counter/migrations/0024_data_migration_remove_useless_entities_and_updated_relations.py

@@ -99,6 +99,9 @@ def fix_models(apps, schema_editor):
         for item in keep_weeks.items():
             week = item[1]
             year_numbers = item[0].split("_")[:-1]
+            # Handle erroneous weeks without a year.
+            if year_numbers == [""]:
+                continue
             week.years.clear()
             for year_number in year_numbers:
                 week.years.add(keep_years[year_number])