Replace use of assert statements in vlan.py
Replace use of assert statements in vlan.py

anarkiwi/faucet,shivarammysore/faucet,anarkiwi/faucet,trungdtbk/faucet,trentindav/faucet,gizmoguy/faucet,mwutzke/faucet,trungdtbk/faucet,wackerly/faucet,REANNZ/faucet,faucetsdn/faucet,gizmoguy/faucet,shivarammysore/faucet,trentindav/faucet,faucetsdn/faucet,REANNZ/faucet,wackerly/faucet,mwutzke/faucet