extractVerticesEdges.py

import pymongo as pm

client = pm.MongoClient()
db = client.instagram
followerIds = db.followerIds

pipeline = [{"$unwind": "$follows"}]

relationships = list(followerIds.aggregate(pipeline))
userIds = list(followerIds.aggregate([{"$match": {"follows": {"$exists": True}}},{"$project": {"_id": 1}}]))

edgesList = []
for relationship in relationships:
    edgesList.append(tuple([str(relationship['_id']), str(relationship['followers']), 'followed_by']))