diff --git a/zerver/lib/actions.py b/zerver/lib/actions.py
index 497e8b2ea9..95ff2b80a9 100644
--- a/zerver/lib/actions.py
+++ b/zerver/lib/actions.py
@@ -456,7 +456,7 @@ def notify_created_bot(user_profile: UserProfile) -> None:
     event = created_bot_event(user_profile)
     send_event(user_profile.realm, event, bot_owner_user_ids(user_profile))
 
-def create_users(realm: Realm, name_list: Iterable[Tuple[str, str]], bot_type: int=None) -> None:
+def create_users(realm: Realm, name_list: Iterable[Tuple[str, str]], bot_type: Optional[int]=None) -> None:
     user_set = set()
     for full_name, email in name_list:
         short_name = email_to_username(email)
@@ -5317,7 +5317,7 @@ def notify_realm_custom_profile_fields(realm: Realm, operation: str) -> None:
 
 def try_add_realm_custom_profile_field(realm: Realm, name: str, field_type: int,
                                        hint: str='',
-                                       field_data: ProfileFieldData=None) -> CustomProfileField:
+                                       field_data: Optional[ProfileFieldData]=None) -> CustomProfileField:
     field = CustomProfileField(realm=realm, name=name, field_type=field_type)
     field.hint = hint
     if field.field_type == CustomProfileField.CHOICE:
@@ -5342,7 +5342,7 @@ def do_remove_realm_custom_profile_fields(realm: Realm) -> None:
 
 def try_update_realm_custom_profile_field(realm: Realm, field: CustomProfileField,
                                           name: str, hint: str='',
-                                          field_data: ProfileFieldData=None) -> None:
+                                          field_data: Optional[ProfileFieldData]=None) -> None:
     field.name = name
     field.hint = hint
     if field.field_type == CustomProfileField.CHOICE: