[Python] string argument expected, got bytes. in npytar.py

I'm trying to convert .mat files into a tar file, which consists of compressed .npy files. I'm using a modified version of npytar.py from Voxnets. I am using io.BytesIO() as some other people have previously suggested. From what I can gather from the. Does anyone have any solutions?

This is the code referred to in the traceback of Line 53.

logging.info('Saving train npy tar file')
train_records = records['train']
random.shuffle(train_records)
write(train_records,'shapenet10_train.tar')


And here is the code for the traceback at line 19

def write(records, fname):
writer = npytar.NpyTarWriter(fname)
for (classname, instance, rot, fname) in records:
class_id = int(shapenet10.class_name_to_id[classname])
name = '{:03d}.{}.{:03d}'.format(class_id, instance, rot)
arr = scipy.io.loadmat(fname)['instance'].astype(np.uint8)
arrpad = np.zeros((32,)*3, dtype=np.uint8)
arrpad[1:-1,1:-1,1:-1] = arr
writer.add(arrpad, name)
writer.close()


import io
import numpy as np

...
def add(self, arr, name):

sio = io.BytesIO()
np.save(sio, arr)
zbuf = zlib.compress(sio.getvalue())
sio.close()

zsio = io.BytesIO(zbuf)
tinfo = tarfile.TarInfo('{}{}{}'.format(PREFIX, name, SUFFIX))
tinfo.size = len(zbuf)
tinfo.mtime = time.time()
zsio.seek(0)
self.tfile.addfile(tinfo, zsio)
zsio.close()
...



Traceback (most recent call last):
File "C:\Users\yahya\PycharmProjects\Final_Year_Project\convert_shapenet10.py", line 53, in <module>
write(train_records,'shapenet10_train.tar')
File "C:\Users\yahya\PycharmProjects\Final_Year_Project\convert_shapenet10.py", line 19, in write
writer.add(arrpad, name)
File "C:\Users\yahya\PycharmProjects\Final_Year_Project\npytar.py", line 19, in add
format.write_array(fid, arr, allow_pickle=allow_pickle,
File "C:\Users\yahya\PycharmProjects\Final_Year_Project\.venv\Lib\site-packages\numpy\lib\format.py", line 724, in write_array
_write_array_header(fp, header_data_from_array_1_0(array), version)
File "C:\Users\yahya\PycharmProjects\Final_Year_Project\.venv\Lib\site-packages\numpy\lib\format.py", line 467, in _write_array_header
fp.write(header)
TypeError: string argument expected, got 'bytes'

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