Can't be bothered to watch a tcpdump filter to work out an available IP address?
Try arpy.
Grab this repo, and install scapy if you don't have it already. I'm using the AsyncSniffer, so you will want to install scapy v2.4.3 or greater.
git clone git@github.com:michaelranaldo/arpy
pip install scapy
sudo python3.x arpy.pyPython 3, requires sudo.