The problem with using openmc_to_cad

[wwwo-dx123]

What is the reason for the following error when I am using openmc_to_cad?
Traceback (most recent call last):
File "/home/lee/anaconda3/envs/openmc-env/bin/openmc_to_cad", line 8, in
sys.exit(openmc_to_cad())
File "/home/lee/anaconda3/envs/openmc-env/lib/python3.10/site-packages/openmc_cad_adapter/to_cubit_journal.py", line 628, in openmc_to_cad
to_cubit_journal(model.geometry, world=args.world_size, filename=args.output, cells=args.cells, to_cubit=args.to_cubit)
File "/home/lee/anaconda3/envs/openmc-env/lib/python3.10/site-packages/openmc_cad_adapter/to_cubit_journal.py", line 548, in to_cubit_journal
do_cell( cell )
File "/home/lee/anaconda3/envs/openmc-env/lib/python3.10/site-packages/openmc_cad_adapter/to_cubit_journal.py", line 523, in do_cell
vol_or_body = process_node_or_fill( cell, w )
File "/home/lee/anaconda3/envs/openmc-env/lib/python3.10/site-packages/openmc_cad_adapter/to_cubit_journal.py", line 363, in process_node_or_fill
id = process_node_or_fill( node.fill, w, indent + 1, offset, inner_world )
File "/home/lee/anaconda3/envs/openmc-env/lib/python3.10/site-packages/openmc_cad_adapter/to_cubit_journal.py", line 468, in process_node_or_fill
r = ( len( uss ) - i -1 ) * pitch[0]
UnboundLocalError: local variable 'uss' referenced before assignment

plane1 = openmc.ZPlane(z0 = 0 , boundary_type='reflective')
plane2 = openmc.ZPlane(z0 = 20 , boundary_type='reflective')
r1 = openmc.ZCylinder(r = 0.45)
r2 = openmc.ZCylinder(r = 0.5)

s1 = openmc.YPlane(y0 = 4.335,  boundary_type='reflective')
s2 = openmc.Plane(1.7320508076, 1, 0, 8.67,  boundary_type='reflective')
s3 = openmc.Plane(1.7320508076, -1, 0, 8.67,  boundary_type='reflective')
s4 = openmc.YPlane(y0 = -4.335,  boundary_type='reflective')
s5 = openmc.Plane(1.7320508076, 1, 0, -8.67,  boundary_type='reflective')
s6 = openmc.Plane(1.7320508076, -1, 0, -8.67,  boundary_type='reflective')

cell1 = openmc.Cell(fill = m1, region = -r1 & -plane2  & +plane1)
cell3 = openmc.Cell(fill = m5, region = +r1 & -plane2  & +plane1)

u9000 = openmc.Universe()
u9000.add_cells([cell1,cell3])

outer = openmc.Cell(fill = m5)
outer_un = openmc.Universe(cells = (outer,) )

hexlat90 = openmc.HexLattice()
hexlat90.center = (0,0)
hexlat90.pitch = [1.4]  
hexlat90.outer = outer_un

outer_ring = [u9000] * 18
third_ring = [u9000] * 12
middle_ring = [u9000] * 6 
inner_ring = [u9000]
hexlat90.universes = [outer_ring, third_ring, middle_ring, inner_ring]
hexlat90.orientation = 'x'

main_cell0 = openmc.Cell(fill=hexlat90, region = -plane2  & +plane1
                         & -s1 & -s2 & -s3 & +s4 & +s5 & +s6)
hex0 = openmc.Universe(cells = (main_cell0, ))

geom = openmc.Geometry(hex0)
# geom.orientation = 'x'
# geom.export_to_xml()