Use `.iterator()` from peewee when querying

Closes #15 (closed)

worker_generic_training_dataset/db.py

@@ -17,11 +17,13 @@ def retrieve_element(element_id: UUID) -> Element:
 
 
 def list_classifications(element_id: UUID):
-    return Classification.select().where(Classification.element == element_id)
+    return (
+        Classification.select().where(Classification.element == element_id).iterator()
+    )
 
 
 def list_transcriptions(element_id: UUID):
-    return Transcription.select().where(Transcription.element == element_id)
+    return Transcription.select().where(Transcription.element == element_id).iterator()
 
 
 def list_transcription_entities(transcription_id: UUID):
@@ -30,4 +32,5 @@ def list_transcription_entities(transcription_id: UUID):
         .where(TranscriptionEntity.transcription == transcription_id)
         .join(Entity, on=TranscriptionEntity.entity)
         .join(EntityType, on=Entity.type)
+        .iterator()
     )