@user_router.get("/")
def get_users():
    return [{"user_id": "u1"}, {"user_id": "u2"}]


@user_router.get("/{user_id}")
def get_user(user_id: str):
    return {"user_id": user_id}


@item_router.get("/")
def get_items(user_id: Optional[str] = None):
    if user_id is None:
        return [{"item_id": "i1", "user_id": "u1"}, {"item_id": "i2", "user_id": "u2"}]
    else:
        return [{"item_id": "i2", "user_id": user_id}]

'dropdown-menu',\n  ACTIVE        : 'active'\n}\n\nconst Selector = {\n  DATA_SPY        : '[data-spy=\"scroll\"]',\n  ACTIVE          : '.active',\n  NAV_LIST_GROUP  : '.nav, .list-group',\n  NAV_LINKS       : '.nav-link',\n  NAV_ITEMS       : '.nav-item',\n  LIST_ITEMS      : '.list-group-item',\n  DROPDOWN        : '.dropdown',\n  DROPDOWN_ITEMS  : '.dropdown-item',\n  DROPDOWN_TOGGLE : '.dropdown-toggle'\n}\n\nconst OffsetMethod = {\n  OFFSET   : 'offset',\n  POSITION : 'position'\n}\n\n/**\n * ------------...