Use `.iterator()` from peewee when querying

Closes #15 (closed)

worker_generic_training_dataset/worker.py

@@ -329,7 +329,7 @@ class DatasetExtractor(DatasetWorker):
             # List children
             children = list_children(element.id)
             nb_children: int = children.count()
-            for child_idx, child in enumerate(children, start=1):
+            for child_idx, child in enumerate(children.iterator(), start=1):
                 logger.info(f"Processing child ({child_idx}/{nb_children})")
                 # Insert child
                 self.insert_element(child, parent_id=element.id)