ERROR: MATLAB type not supported: struct, (uint64)

[afonsobspinto]

Hi! How's it going?
I attempted to load the .mat file available here like shown:

mat73.loadmat('atlas_index.mat', use_attrdict=True)

(The behavior is replicated with or without the use_attrdict flag.)

but it failed with the error:

ERROR:root:ERROR: MATLAB type not supported: struct, (uint64)
Traceback (most recent call last):
  File "/home/afonso/anaconda3/envs/mgv/lib/python3.7/site-packages/mat73/__init__.py", line 226, in loadmat
    dictionary = decoder.mat2dict(hdf5, only_load=only_load)
  File "/home/afonso/anaconda3/envs/mgv/lib/python3.7/site-packages/mat73/__init__.py", line 52, in mat2dict
    d[var] = self.unpack_mat(hdf5[var])
  File "/home/afonso/anaconda3/envs/mgv/lib/python3.7/site-packages/mat73/__init__.py", line 77, in unpack_mat
    unpacked = self.unpack_mat(elem, depth=depth+1)
  File "/home/afonso/anaconda3/envs/mgv/lib/python3.7/site-packages/mat73/__init__.py", line 108, in unpack_mat
    return self.convert_mat(hdf5)
  File "/home/afonso/anaconda3/envs/mgv/lib/python3.7/site-packages/mat73/__init__.py", line 151, in convert_mat
    entry = self.unpack_mat(self.refs.get(r))
  File "/home/afonso/anaconda3/envs/mgv/lib/python3.7/site-packages/mat73/__init__.py", line 77, in unpack_mat
    unpacked = self.unpack_mat(elem, depth=depth+1)
  File "/home/afonso/anaconda3/envs/mgv/lib/python3.7/site-packages/mat73/__init__.py", line 77, in unpack_mat
    unpacked = self.unpack_mat(elem, depth=depth+1)
  File "/home/afonso/anaconda3/envs/mgv/lib/python3.7/site-packages/mat73/__init__.py", line 80, in unpack_mat
    values = unpacked.values()
AttributeError: 'NoneType' object has no attribute 'values'

Versions:
mat73==0.50
numpy==1.20.3