title: DynamoDB BatchWriteItem: Provided list of item keys contains duplicates
body: <p>I am trying to use DynamoDB operation <code>BatchWriteItem</code>, wherein I want to insert multiple records into <strong>one</strong> table.</p>
  <p>This table has one partition key and one sort key.</p>
  <p>I am using AWS lambda and Go language.</p>
  <p>I get the elements to be inserted into a slice.</p>
  <p>I am following this procedure.</p>
  <ol>
  <li><p>Create <code>PutRequest</code> structure and add AttributeValues for the first record from the list.</p>
  </li>
  <li><p>I am creating <code>WriteRequest</code> from this <code>PutRequest</code></p>
  </li>
  <li><p>I am adding this <code>WriteRequest</code> to an <code>array of WriteRequests</code></p>
  </li>
  <li><p>I am creating <code>BatchWriteItemInput</code> which consists of <code>RequestItems</code>, which  is basically a <strong>map of Tablename</strong> and the array of <code>WriteRequests</code>.</p>
  </li>
  </ol>
  <p>After that I am calling <code>BatchWriteItem</code>, which results into an error:</p>
  <pre><code>Provided list of item keys contains duplicates.
  </code></pre>
  <p>Any pointers, why this could be happening?</p>