Not obvious how to set up 2 authorisaton keys for 2 channels within 1 client

[Gerriko]

I might have misunderstood how things work, so apologies if that's the case.

I am using the Pubnub's Debug Console as my guide. Here I can set up individual authorisation keys for different channels.

Within the Arduino library code there is set_auth(const char* auth) { d_auth = auth; }

but this sets up an authorization key/token for a PubNub client.

How can the code/library be changed so that a separate auth key can be used for publish and subscribe.