Using swallow_csv - Usage Error

I am running some MATLAB code from another developer which uses swallow_csv; I am running the code on Windows 10 and I keep getting a usage error no matter what I do. The syntax is verbatim so not sure why it doesn't like the usage? I did try rebuilding the mexw64 file from the swallow_csv.cpp file. Any suggestions?

quote = ‘”‘;
sep = ‘,’;
escape = ‘\’;
[raw, text] = swallow_csv(filename, quote, sep, escape);


Error using swallow_csv
Usage: [numbers, text] = swallow_csv(filename, [quote, [sep, [escape]]])

[Walter Roberson]

This appears to refer to https://adared.ch/efficient-csv-reader-for-matlab/

[Walter Roberson]

what is class(filename) ?