public function offsetGet($rendition)
{
return array_key_exists((string) $rendition, $this->renditions) ? $this->renditions[(string) $rendition] : ($this->defaultImage !== null && $rendition->fits($this->defaultImage) ? $this->renditions[(string) $rendition] = new DefaultArticleRendition($this->articleNumber, $rendition, $this->defaultImage) : null);
}