ABP - troubleshooting first connection attempt

[dws]

I'm new to LoRA and am attempting to get a LoPy 4 to connect to a known working gateway. I'm running the ABP code from here: https://docs.pycom.io/tutorials/lora/lorawan-abp.html and I'm trying to figure out if it's actually working. It doesn't throw an error, it just ends after printing b''. In a attempt at troubleshooting I printed out the value returned by the join() function, and that is "None". The API does not specify what this function returns, if anything, so I don't know if None is conclusive.

I see no data associated with my app / device in the TTN console.

I am looking at everything and wondering what the '00000005' value is in this line, I'm assuming this should be the Device Address from the TTN console:

dev_addr = struct.unpack(">l", ubinascii.unhexlify('00000005'))[0]

This is not documented in the API from what I can tell.

Bottom line is, how do I know when I've joined a gateway if the gateway returns no data, i.e if socket.recv() returns no data?

thanks