2D-all?

[berni via Digitalmars-d-learn]

I've got a lot of code with two-dimensional arrays, where I use 
stuff like:

assert(matrix.all!(a=>a.all!(b=>b>=0)));

Does anyone know if there is a 2D-version of all so I can write 
something like:

assert(matrix.all2D!(a=>a>=0));