title: Create mongodb user from python
body: <p>I am trying to create a db user from Python with pymongo. But I keep getting pymongo.errors.OperationFailure: CMD_NOT_ALLOWED: createUser error</p>
  
  <pre><code>client = MongoClient("mongodb+srv://username:password@mycluster-mogiz.mongodb.net/admin")
  db = client["testDB"]
  db.command("createUser", "user", pwd="password")
  </code></pre>
  
  <p>am I missing something? Thanks.</p>
  
  <p>Note: my db is on Mongo Atlas don't know if this changes anything.</p>