[firedrake] Projecting CG1 function into DG0 function

Hi all, Perhaps this may be a simple question, but say I have this bilinear and linear form: a = grad(u)*D*grad(v)*dx L = F*v*dx where u,v is trial/test function on CG1 space, and D and F are coefficients that live in DG0 space. Say I have a velocity vector function q (CG1) on the same mesh and want D to be the element-wise divergence of said velocity. How would I formulate D in Firedrake? Thanks, Justin