Symfony\Component\DependencyInjection\Definition::getTag PHP Method

    public function getTag($name)
    {
        return isset($this->tags[$name]) ? $this->tags[$name] : array();
    }

 /**
  * @param Definition $formDefinition
  *
  * @return string Form name
  */
 private function getFormName(Definition $formDefinition)
 {
     $tags = $formDefinition->getTag('form.type');
     $formName = isset($tags[0]['alias']) ? $tags[0]['alias'] : null;
     if (null === $formName) {
         throw new \InvalidArgumentException(sprintf('Definition "%s" tagged by "%s" should also be tagged by "%s" with attribute "%s"', $formDefinition->getClass(), 'sylius.metadata.dynamic_form', 'form.type', 'alias'));
     }
     return $formName;
 }