app = FastAPI()


class RecursiveItem(BaseModel):
    sub_items: list["RecursiveItem"] = []
    name: str


class RecursiveSubitemInSubmodel(BaseModel):
    sub_items2: list["RecursiveItemViaSubmodel"] = []
    name: str


class RecursiveItemViaSubmodel(BaseModel):
    sub_items1: list[RecursiveSubitemInSubmodel] = []
    name: str


RecursiveItem.model_rebuild()