refactor: using optional keyword

schemas/board.py

@@ -1,3 +1,5 @@
+from typing import Optional
+
 from schemas.base import BaseSchema, BaseResponse
 
 
@@ -14,8 +16,8 @@ class BoardSchema(BaseBoardSchema):
 
 
 class UpdateBoardSchema(BaseSchema):
-    name: str | None = None
-    lexorank: str | None = None
+    name: Optional[str] = None
+    lexorank: Optional[str] = None
 
 
 # endregion