docs: function DummyError() {
    var code = arguments[0]
      , args = Array.prototype.slice.call(arguments, 1)
      , msgi = (typeof args[0] === 'object') ? 1 : 0
    ;
    // Apply code to error message composed by parent class.
    args[msgi] = code + ', ' + args[msgi];
    // Construct parent.
    VError.apply(this, args);
    // Define DummyError specific attributes.
    this.name = 'DummyError';
    this.code = code || 'DEFAULT';
    this.errno = DUMMY_ERRNOS[this.code];
  }