followOtherFollowers.py

import sys
import os
sys.path.append(os.path.abspath("yourpath/Instagram-API-python/InstagramAPI"))
from InstagramAPI import InstagramAPI
import time
import random
import requests

def getUID(usernameTarget):
    r = requests.get('https://www.instagram.com/' + usernameTarget+ '/?__a=1')
    parsed_r = r.json()
    return parsed_r['user']['id']

user = 'yourname'
pwd = 'yourpass'

uID = getUID('instaUsername') # user ID whose followers are to be followed

api = InstagramAPI(user, pwd)
api.login()

api.getUserFollowers(uID)
users = api.LastJson['users']

for user in users:
    api.follow(user['pk'])
    print 'this user is followed'
    print '====================='
    time.sleep(random.randint(30, 480)) # have some time to wait to prevent instagram suspend