Neos.Media/Classes/Domain/Model/AssetCollection.php
public function addTag(Tag $tag)
    {
        if (!$this->tags->contains($tag)) {
            $this->tags->add($tag);
            return true;
        }
        return false;
    }
public function addTag(Tag $tag)
    {
        if (!$this->tags->contains($tag)) {
            $this->tags->add($tag);
            return true;
        }
        return false;
    }
public function addTag ( Tag $ tag ) { if ( ! $ this -> tags -> contains ( $ tag ) ) { $ this -> tags -> add ( $ tag ) ; return true ; } return false ; }
Add a single tag to this asset

@param Tag $tag
@return boolean
Add a single tag to this asset