Convertion issue nf2_to_vtk

[Ivan-Tang]

I met a convertion issue when using nf2.convert.nf2_to_vtk module
Here is the command I used

python -m nf2.convert.nf2_to_vtk --nf2_path ./extrapolation_result.nf2 --out_path ./visuals/volume_0_36.vtk --Mm_per_pixel 0.36 --height_range 0 36 --metrics 'j'
Load NF2: 100%|████████████████████████████████████████████████████████| 7837/7837 [27:05<00:00,  4.82it/s]
Exception in thread Thread-2:
Traceback (most recent call last):
  File "/opt/anaconda3/envs/nf2/lib/python3.10/threading.py", line 1016, in _bootstrap_inner
    self.run()
  File "/Users/IvanTang/Solarphysics/NF2/nf2/convert/nf2_to_vtk.py", line 26, in run
    save_vtk(self.out_path, vectors=vectors, scalars=scalars, Mm_per_pix=Mm_per_pixel)
  File "/Users/IvanTang/Solarphysics/NF2/nf2/evaluation/vtk.py", line 34, in save_vtk
    sg = tvtk.StructuredGrid(dimensions=dim, points=pts)
  File "tvtk_classes/structured_grid.py", line 65, in __init__
  File "/opt/anaconda3/envs/nf2/lib/python3.10/site-packages/tvtk/tvtk_base.py", line 427, in __init__
    super(TVTKBase, self).__init__(**traits)
traits.trait_errors.TraitError: Cannot set the undefined 'dimensions' attribute of a 'StructuredGrid' object.