Doctrine\Common\Collections\ArrayCollection::contains PHP Method

    public function contains($element)
    {
        return in_array($element, $this->elements, true);
    }

 /**
  * @param BreadcrumbManagerInterface $manager
  */
 public function addManager(BreadcrumbManagerInterface $manager)
 {
     if ($this->managers->contains($manager)) {
         return;
     }
     $this->managers->add($manager);
 }