check_duplicate_ip.py

import collections
from subprocess import Popen, PIPE

def execute_cmd(cmd):
    sub = Popen(cmd, stdout=PIPE, stderr=PIPE, shell=True)
    out, err = sub.communicate()
    return out, err

out, err = execute_cmd('ip n')
ip_n_data = str(out)
ip_n_data = ip_n_data.replace('\n', ' ')
node_ips = []
for data in ip_n_data.split(' '):
    if "172.20" in data:
        node_ips.append(data)

print([item for item, count in collections.Counter(node_ips).items() if count > 1])

from IPython import embed
embed()