compute multisphere

I am having trouble extracting data using "compute multisphere". I added the line "compute multi all multisphere property xcm" to the in.multisphere example file just below the already-existing compute command. I then run in.multisphere through the python interface by typing:

from lammps import lammps
lmp=lammps()
lmp.file('in.multisphere')

The file ran fine on 1 processor and all output seemed normal. Then I attempted to extract the value from the compute by typing: xcm = lmp.extract_compute('multi',1,0).

The object returned to xcm is a 'NoneType' object. When I tried the same process with "compute atomprop all property/atom id x y z vx vy vz fx fy fz" I was able to extract an array of per-atom data without any issues in python. But I need to be able to compute multisphere properties such as xcm and quat. Can someone please explain how I can extract multisphere data in python or to a dump file using compute multisphere? Is there any sort of workaround to do this?

If it's relevant, there is also no compute_multisphere.cpp file in the downloaded source code, but compute_rigid.cpp exists.