Recommended Shake256 digest size for KMAC based HKDF

On the wiki page for HKDF, in the Python Implementation, there is a hash_length variable for the sha256 digest length, used in the hmac in the hmac_sha256 function.

However, if I wanted to replace the hmac with a kmac, I would have to change the hmac(...) into kmac(...), where the underlying hash algorithm is the shake256 algorithm (XOF) - with variable output length.

So my question is what is the recommended length to set the shake256 digest size to when incorporating it into a KMAC based HKDF?