pub type KpType<'a, R, V> = Kp<R, V, &'a R, &'a V, &'a mut R, &'a mut V, for<'b> fn(&'b R) -> Option<&'b V>, for<'b> fn(&'b mut R) -> Option<&'b mut V>>;
pub struct KpType<'a, R, V> { /* private fields */ }