Scapy arp ping with nmap vendor mac-prefix

#!/usr/bin/env python
# note that this script requires tcpdump to be installed
# additionally, it requires root privs to run.

import sys
import logging
logging.getLogger("scapy.runtime").setLevel(logging.ERROR)

if len(sys.argv) != 2:
    print "Usage: pingarp \n  eg: pingarp 192.168.1.0/24"
    sys.exit(1)

filename = '/usr/share/nmap/nmap-mac-prefixes' # '/usr/local/share/nmap/nmap-mac-prefixes'
vals = {}
with open(filename) as myFile:
    for line in myFile.readlines():
        vals[line[:6]] = line[7:-1]

from scapy.all import srp,Ether,ARP,conf, Dot11Elt
conf.verb=0
ans,unans=srp(Ether(dst="ff:ff:ff:ff:ff:ff")/ARP(pdst=sys.argv[1]),
              timeout=2)

for snd,rcv in ans:
    val = rcv.sprintf(r"%Ether.src%").replace(":", "")[:6].upper()
    print rcv.sprintf(r"%Ether.src%, %ARP.psrc%"), "(%s)" % vals[val] if val in vals else '(Not found)'