diff --git a/packages/api-server/api_server/query.py b/packages/api-server/api_server/query.py
index 8ae4347d8..b04c3d565 100644
--- a/packages/api-server/api_server/query.py
+++ b/packages/api-server/api_server/query.py
@@ -8,7 +8,7 @@
 def add_pagination(
     query: QuerySet[MODEL],
     pagination: Pagination,
-    field_mappings: Dict[str, str] = {},
+    field_mappings: Optional[Dict[str, str]] = None,
 ) -> QuerySet[MODEL]:
     """
     Adds pagination and ordering to a query.
@@ -17,6 +17,7 @@ def add_pagination(
         query. e.g. a url of `?order_by=order_field` and a field mapping of `{"order_field": "db_field"}`
         will order the query result according to `db_field`.
     """
+    field_mappings = field_mappings or {}
     query = query.limit(pagination.limit).offset(pagination.offset)
     if pagination.order_by is not None:
         order_fields = []
diff --git a/packages/api-server/api_server/routes/tasks/tasks.py b/packages/api-server/api_server/routes/tasks/tasks.py
index 1704ce312..ebe6e06a6 100644
--- a/packages/api-server/api_server/routes/tasks/tasks.py
+++ b/packages/api-server/api_server/routes/tasks/tasks.py
@@ -3,8 +3,6 @@
 
 from fastapi import Body, Depends, HTTPException, Path, Query
 from rx import operators as rxops
-from tortoise.expressions import Case, F, Q, RawSQL, Subquery, When
-from tortoise.functions import Max
 
 from api_server import models as mdl
 from api_server.dependencies import (