  <tr>
          <td><code>required_columns</code></td>
          <td>
                <code>list or set</code>
          </td>
          <td><p>The names of the columns that are required for this transformation. This argument is made mandatory
because it's often trivial to supply and can often greatly speed things up.</p></td>
          <td>
              <em>required</em>
          </td>
        </tr>
    </tbody>
  </table>

<details class="return">
  <summary>Return</summary>
  <p>A transformed DataStre