src/Traits/Mergeable.php
public static function merge(Model $model1, Model $model2, array $attributes)
    {
        foreach ($attributes as $attribute) {
            $model1->$attribute = $model2->$attribute;
        }
        return $model1;
    }
public static function merge(Model $model1, Model $model2, array $attributes)
    {
        foreach ($attributes as $attribute) {
            $model1->$attribute = $model2->$attribute;
        }
        return $model1;
    }
Merge models.

@param Model $model1
@param Model $model2
@param array $attributes
@return Model