77  }
        </pre>

        <p>
            And <tt>ValidateParams</tt> looks like this:
        </p>

        <pre>
    149  template &lt;typename T&gt;
    150  bool ValidateParams(const Pointer&lt;T&gt;& input,
    151                      ValidationContext* validation_context) {
    152    if (validation_context-&gt;ExceedsMaxDepth()) {
    153      ReportValidationError(validation_context,
    154                            VALIDATION_ERROR_MAX_RECURSION_DEPTH);
    155      return false;
    156    