bridge/doctrine-collections/lib/CollectionsAgent.php
public function find($identifier, string $classFqn = null)
    {
        if (null === $classFqn) {
            throw BadMethodCallException::classArgumentIsMandatory(__CLASS__);
        }

        $object = $this->store->find($classFqn, $identifier);

        if (null === $object) {
            throw ObjectNotFoundException::forClassAndIdentifier($classFqn, $identifier);
        }

        return $object;
    }
public function find($identifier, string $classFqn = null)
    {
        if (null === $classFqn) {
            throw BadMethodCallException::classArgumentIsMandatory(__CLASS__);
        }

        $object = $this->store->find($classFqn, $identifier);

        if (null === $object) {
            throw ObjectNotFoundException::forClassAndIdentifier($classFqn, $identifier);
        }

        return $object;
    }
{@inheritdoc}