Fix a type annotation in `test_account_data.py` and remove it from the Mypy exclusion list. (#11657)

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/tests/storage/test_account_data.py b/tests/storage/test_account_data.py
index 01af49a16b..d697d2bc1e 100644
--- a/tests/storage/test_account_data.py
+++ b/tests/storage/test_account_data.py
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import Iterable, Set
+from typing import Iterable, Optional, Set
 
 from synapse.api.constants import AccountDataTypes
 
@@ -25,7 +25,7 @@ class IgnoredUsersTestCase(unittest.HomeserverTestCase):
         self.user = "@user:test"
 
     def _update_ignore_list(
-        self, *ignored_user_ids: Iterable[str], ignorer_user_id: str = None
+        self, *ignored_user_ids: Iterable[str], ignorer_user_id: Optional[str] = None
     ) -> None:
         """Update the account data to block the given users."""
         if ignorer_user_id is None: