def main():
    parser = argparse.ArgumentParser('usage %prog ' + '--host --host_file --username --password  --enable --group --snmp_user --snmp_host --int_name --snmp_v3_auth --snmp_v3_hmac --snmp_v3_priv --snmp_v3_encr')
    parser.add_argument('--host', dest='host', type=str, help='specify a target host')
    parser.add_argument('--host_file', dest='hfile', type=str, help='specify a target host file')

    host = args.host
    hfile = args.hfile

    if hfile:
        with open(hfile) as hosts:
            for line in hosts:
                host = line.rstrip()
                child = connects(user, host, passwd, en_passwd)
                send_command(child, SNMPGROUPCMD + group + V3PRIVCMD)
                send_command(child, SNMPSRVUSRCMD + snmpuser + ' ' + group + V3AUTHCMD + SHAHMACCMD + snmpauth + PRIVCMD + snmpencrypt + ' ' + snmppriv)
                send_command(child, SNMPSRVHOSTCMD + intname + ' ' + snmphost + VERSION3CMD + snmpuser)
                send_command(child, SNMPSRVENTRAP)
                send_command(child, WRME)
    elif host:
        child = connect(user, host, passwd, en_passwd)
        send_command(child, SNMPGROUPCMD + group + V3PRIVCMD)
        send_command(child, SNMPSRVUSRCMD + snmpuser + ' ' + group + V3AUTHCMD + SHAHMACCMD + snmpauth + PRIVCMD + snmpencrypt + ' ' + snmppriv)
        send_command(child, SNMPSRVHOSTCMD + intname + ' ' + snmphost + VERSION3CMD + snmpuser)
        send_command(child, SNMPSRVENTRAP)
        send_command(child, WRME)
    else:
        print('Specify either --host or --host-file or I have nothing to do')