pub fn tensor_len_ok(dims: &[usize], bits_per_item: usize, data_size_bytes: usize) -> bool {
    let mut len = 1usize;
    let mut i = 0usize;
    while i < dims.len() {
        len = len * dims[i];
        i += 1;
    }
    len * (bits_per_item / 8) == data_size_bytes
}