public function link($entity, $attribute)
    {
        $this->entity = $entity;
        $this->attribute = $attribute;

        return $this;
    }
public function link($entity, $attribute)
    {
        $this->entity = $entity;
        $this->attribute = $attribute;

        return $this;
    }
public function link ( $ entity , $ attribute ) { $ this -> entity = $ entity ; $ this -> attribute = $ attribute ; return $ this ; }
Link the entity and attribute to this value collection.

@param \Illuminate\Database\Eloquent\Model $entity
@param $attribute

@return $this
Link the entity and attribute to this value collection .