refactor: using optional keyword

schemas/base.py

@@ -1,4 +1,4 @@
-from typing import Self
+from typing import Self, Optional
 
 from pydantic import BaseModel
 from pydantic.alias_generators import to_camel
@@ -36,8 +36,8 @@ class BaseResponse(BaseSchema):
 
 
 class PaginationSchema(BaseSchema):
-    page: int | None = None
-    items_per_page: int | None = None
+    page: Optional[int] = None
+    items_per_page: Optional[int] = None
 
 
 class PaginationInfoSchema(BaseSchema):