title: Error on getting aws account root user details using boto3
body: <p>I am trying to get the root user details in an AWS account in lambda function using boto3, however it gives the below error.</p>
  
  <pre><code>"errorMessage": "An error occurred (NoSuchEntity) when calling the GetUser operation: The user with name root cannot be found.",
  "errorType": "NoSuchEntityException"
  </code></pre>
  
  <p>Code Snippet:</p>
  
  <pre><code>import boto3
  client = boto3.client('iam')
  response = client.get_user(
  UserName='root'
  )
  </code></pre>