[firedrake] .array()

Dear Firedrake team, i'm trying to get u*v*dx as a array which each component is amount of the integral on each element. I want to do that in order to compute error indicator. In dolfin implementation it be done like: assemble(u*v*dx).array() Is there a way to do this in Firedrake? Runing the above code in Firedrake gives: AttributeError: 'numpy.float64' object has no attribute 'array' Thank you in advance. Best, Amireh