diff --git a/moto/organizations/models.py b/moto/organizations/models.py
index 7c241b9d958a..3f036076ac14 100644
--- a/moto/organizations/models.py
+++ b/moto/organizations/models.py
@@ -483,7 +483,9 @@ def delete_organization(self) -> None:
 
     def list_roots(self) -> Dict[str, Any]:
         if self.org:
-            return dict(Roots=[ou.describe() for ou in self.ou if isinstance(ou, FakeRoot)])
+            return dict(
+                Roots=[ou.describe() for ou in self.ou if isinstance(ou, FakeRoot)]
+            )
 
         if self.account_id in organizations_backends.master_accounts:
             master_account_id, partition = organizations_backends.master_accounts[