SELECT procedure result into_tuple without a FROM clause?

[Expurple]

I want to execute a stored procedure in Postgres. Currently, I have to bring an unrelated entity foo, which is confusing:

models::foo::Entity::find()
    .select_only()
    .expr(Expr::cust_with_values("my_procedure($1)", [some_argument]))
    .into_tuple::<NaiveDate>()
    .one(tx)
    .await

In generates the following SQL, which works:

SELECT my_procedure(...) FROM "foo" LIMIT 1

But I'd like to be able to do something like the following:

sea_orm::select_without_from()
    .expr(Expr::cust_with_values("my_procedure($1)", [some_argument]))
    .into_tuple::<NaiveDate>()
    .one(tx)
    .await

Which would generate:

SELECT my_procedure(...) LIMIT 1