pub fn main(world: World) -> Void raises {
    var values: [4]u8 = [0, 0, 0, 0]
    let dst: MutSpan<u8> = values
    let len: usize = std.collections.push(dst, 0_usize, 1_u8)
    if len == 1 && values[0] == 1_u8 {
        check world.out.write("std collections mutspan memory ok\n")
    }
}