Apple Music API create Developer Token JWT

How can I create a Developer Token to use Apple Music API?
I already got my Key Identifier (kid), Team ID - the issuer (iss) and MusicKit private key but I don't really get how to create a Developer Token at this point.
Check out: https://github.com/ethanhuang13/CupertinoJWT
It works great, might be helpful for you!
Apple Music API create Developer Token JWT
 
 
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