where is cell_domains in >0.9.10

Hi,

I am trying to run my code after updating to the trunk version of dolfin. I noticed that VariationalProblem no longer accepts cell_domains keyword. Do you have an example on how to setup or plan to setup problems with multiple domains? assign_domains bugs with

/usr/local/lib/python2.6/dist-packages/dolfin/fem/formmanipulations.py in assign_domains(fro, to)
      7 def assign_domains(fro=None, to=None):
      8 # Remove me if this gets added to UFL instead.

----> 9 to.cell_domains = fro.cell_domains
     10 to.interior_facet_domains = fro.interior_facet_domains
     11 to.exterior_facet_domains = fro.exterior_facet_domains

AttributeError: 'Form' object has no attribute 'cell_domains'

Thanks,
Chaffra