ven name <b>exists</b> in the current project.
    </td>
    <td></td>
  </tr>

  <tr>
    <td>unless</td>
    <td>Only execute if a property of the given name <b>not exists</b> in the current project.
    </td>
    <td></td>
  </tr>

  <tr>
    <td>value (requiered)</td>
    <td>Second arg for operation
    </td>
    <td></td>
  </tr>

  <tr>
    <td>type</td>
    <td>Value type to express operation (support <em>long</em> and <em>double</em>)
    </td>
    <td><code class="noHighlight">long</code></td>
  <