diff --git a/backend/data_export/pipeline/repositories.py b/backend/data_export/pipeline/repositories.py
index 1423e235..9734b193 100644
--- a/backend/data_export/pipeline/repositories.py
+++ b/backend/data_export/pipeline/repositories.py
@@ -1,7 +1,7 @@
 import abc
 import itertools
 from collections import defaultdict
-from typing import Any, Dict, Iterator, List, Tuple, Union
+from typing import Any, Dict, Iterator, List, Tuple
 
 from .data import Record
 from examples.models import Example
@@ -10,13 +10,12 @@ from projects.models import Project
 SpanType = Tuple[int, int, str]
 
 
-class BaseRepository(abc.ABC):
+class BaseRepository:
     def __init__(self, project: Project):
         self.project = project
 
-    @abc.abstractmethod
     def list(self, export_approved=False) -> Iterator[Record]:
-        pass
+        raise NotImplementedError()
 
 
 class FileRepository(BaseRepository):
@@ -192,7 +191,7 @@ class IntentDetectionSlotFillingRepository(TextRepository):
     def label_per_user(self, doc) -> Dict:
         category_per_user: Dict[str, List[str]] = defaultdict(list)
         span_per_user: Dict[str, List[SpanType]] = defaultdict(list)
-        label_per_user: Dict[str, Dict[str, Union[List[str], List[SpanType]]]] = defaultdict(dict)
+        label_per_user: Dict[str, Dict[str, List]] = defaultdict(dict)
         for a in doc.categories.all():
             category_per_user[a.user.username].append(a.label.text)
         for a in doc.spans.all():