code: public function setVariables($variables, bool $as_instance = true)
      {
          foreach ($variables as $key => $var)
              $this->setVariable($key, $var, $as_instance);
          return $this;
      }
docs: Set multiple variables. A wrapper around AppRunner#setVariable to loop
  over an array.
  @param array|Traversable $variables The variables to set
  @param bool $as_instance To allow referincing this variable by class
  @return AppRunner Provides fluent interface