TypeError: a bytes-like object is required, not 'str'

[SRTA013ORIGINAL]

python sudoku.py /test/test1.jpg
Traceback (most recent call last):
File "sudoku.py", line 42, in
snap_sudoku(image_path=sys.argv[1])
File "sudoku.py", line 32, in snap_sudoku
grid = ''.join(cell for cell in get_cells(image_path))
File "sudoku.py", line 32, in
grid = ''.join(cell for cell in get_cells(image_path))
File "sudoku.py", line 22, in get_cells
net = create_net(rel_path='/networks/net')
File "sudoku.py", line 17, in create_net
sizes, biases, wts = pickle.load(in_file)
TypeError: a bytes-like object is required, not 'str'