return IP address of network interface

IP.py

#(sudo) pip install netifaces
import netifaces as ni
import sys

if name == '__main__':
  interfaces = ni.interfaces()
  if len(sys.argv) < 2:
    print('IP.py interface [json]')
    print('Interfaces: %s' % interfaces)
    quit()
  interface = sys.srgv[1]
  if interface in interfaces:
    address = ni.ifaddresses(interface)[2][0]['addr']
    if sys.argv[2] == 'json':
      print('{"IP": "%s"}' % address)
    else:
      print(address)