title: AWS Dynamodb limits for items size and list item count sounds contradictory
body: <p>Dynamodb documentation [1] clearly states that:  </p>
  
  <ul>
  <li><strong>"Item size"</strong> cannot exceed 400KB.   </li>
  <li><strong>"Number of elements in a list"</strong>: An attribute of type List can contain more than two billion elements.</li>
  </ul>
  
  <p>I must be misunderstanding something here, if you have 2 billion items in a list attribute, then the item containing this attribute is surely larger than 400KB, right?</p>
  
  <p>What am I missing?</p>
  
  <p>1- <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Limits.html" rel="noreferrer">http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Limits.html</a></p>