doc = {'':'','':}
db.users.insert_one(doc)
all_users = list(db.users.find({},'_id':False))
for user in all_users:
print(user)
user = db.users.find_one({'':''})
print(user)
db.users.update_one({'':''},{'$set':{'':}})
db.users.delete_one({'':''})