Please change MAC_TO_FIND = '00:0B:BE:E6:51:80' in MAC_Finder.py, sorry no ARGV :( And add Switches to inventory
$ python3 MAC_Finder.py
TRYING TO FIND MAC: 00:0B:BE:E6:51:80
Found your MAC 00:0B:BE:E6:51:80 on WS-C3550-24-SMI port Vlan1
Found your MAC 00:0B:BE:E6:51:80 on WS-C3550-24-SMI port Vlan800
Found your MAC 00:0B:BE:E6:51:80 on WS-C3550-24-SMI port Vlan3843