Denying a Sign-up request in Cognito User Pools : <p>The description of a Cognito User Pools Pre Sign-up Lambda Trigger is: </p>

<blockquote>
  <p>This trigger is invoked when a user submits their information to sign up, allowing you to perform custom validation to accept or deny the sign up request.</p>
</blockquote>

<p>I want to deny a sign-up request based on a certain condition in my Lambda. The trigger parameters (reproduced from the docs below) seem to only support auto-verification and auto-confirmation: </p>

<pre><code>{
    "request": {
        "userAttributes": {
            "string": "string",
            ....
        },
        "validationData": {
            "string": "string",
            "string": "string",
             ....
        }
    },

    "response": {
        "autoConfirmUser": "boolean",
        "autoVerifyPhone": "boolean",
        "autoVerifyEmail": "boolean"
    }
}
</code></pre>

<p>How can I accept or deny a sign-up request based on the outcome of the Pre Sign-up Lambda Trigger?</p>
