pub trait CwiseRow<'short, Outlives = &'short Self>: Seal {
type Item;
// Required methods
fn ncols(&self) -> usize;
fn is_contiguous(&self) -> bool;
unsafe fn get_unchecked(&'short mut self, i: usize) -> Self::Item;
unsafe fn get_contiguous_unchecked(&'short mut self, i: usize) -> Self::Item;
}