import pymongo
myClient=pymongo.MongoClient("localhost:27017")
mydb=myClient['majorProject']
mycol=mydb['date_modified']

ISBN="0380821001"
book_details=mydb['bookDataset'].find({"ISBN":ISBN})
book_data=list(book_details)
author=book_data[0]['Book-Author']
y=mydb['bookDataset'].find({"Book-Author":{"$regex":author}})
book_authors=list(y)
len(book_authors)