Retrieve transcriptions from local cache in list_transcriptions

Depends on !69 (merged)

Closes #44 (closed)

arkindex_worker/worker.py

@@ -941,16 +941,13 @@ class ElementsWorker(BaseWorker):
                 "worker_version",
             }, "When using the local cache, you can only filter by 'worker_version'"
 
-            conditions = [("element_id", "=", convert_str_uuid_to_hex(element.id))]
+            transcriptions = CachedTranscription.select().where(
+                CachedTranscription.element_id == element.id
+            )
             if worker_version:
-                conditions.append(
-                    ("worker_version_id", "=", convert_str_uuid_to_hex(worker_version))
+                transcriptions = transcriptions.where(
+                    CachedTranscription.worker_version_id == worker_version
                 )
-
-            transcriptions = self.cache.fetch(
-                "transcriptions",
-                where=conditions,
-            )
         else:
             if self.cache:
                 logger.warning(