set correct union nullable return type
set correct union nullable return type

apioo/psx-schema,apioo/psx-schema,apioo/psx-schema,apioo/psx-schema,apioo/psx-schema,apioo/psx-schema,apioo/psx-schema,apioo/psx-schema,apioo/psx-schema,apioo/psx-schema,apioo/psx-schema