<?php namespace Illuminate\Database\Eloquent\Relations\Concerns; use Doctrine\Instantiator\Exception\InvalidArgumentException; trait InteractsWithDictionary { /** * Get a dictionary key attribute - casting it to a string if necessary. * * @param mixed $attribute * @return mixed */ protected function getDictionaryKey($attribute) { if (is_object($attribute)) { if (method_exists($attribute, '__toString')) { return $attribute->__toString(); } throw new InvalidArgumentException('Model attribute value is an object but does not have a __toString method.'); } return $attribute; } }