diff --git a/superset/sql_lab.py b/superset/sql_lab.py
index 2017ad6f0172..9efebfb767ab 100644
--- a/superset/sql_lab.py
+++ b/superset/sql_lab.py
@@ -287,7 +287,9 @@ def execute_sql_statement(  # pylint: disable=too-many-arguments,too-many-locals
     return SupersetResultSet(data, cursor_description, db_engine_spec)
 
 
-def apply_limit_if_exists(database: Database, increased_limit: int, query: Query, sql: str) -> str:
+def apply_limit_if_exists(
+    database: Database, increased_limit: Optional[int], query: Query, sql: str
+) -> str:
     if query.limit and increased_limit:
         # We are fetching one more than the requested limit in order
         # to test whether there are more rows than the limit.
diff --git a/tests/integration_tests/sqllab_tests.py b/tests/integration_tests/sqllab_tests.py
index df09187d557b..6738759b069e 100644
--- a/tests/integration_tests/sqllab_tests.py
+++ b/tests/integration_tests/sqllab_tests.py
@@ -43,7 +43,8 @@
     execute_sql_statements,
     execute_sql_statement,
     get_sql_results,
-    SqlLabException, apply_limit_if_exists,
+    SqlLabException,
+    apply_limit_if_exists,
 )
 from superset.sql_parse import CtasMethod
 from superset.utils.core import (
@@ -1003,7 +1004,6 @@ def test_apply_limit_if_exists_when_incremented_limit_is_none(self):
         assert final_sql == sql
 
 
-
 @pytest.mark.parametrize("spec", [HiveEngineSpec, PrestoEngineSpec])
 def test_cancel_query_implicit(spec: BaseEngineSpec) -> None:
     query = mock.MagicMock()