Fixtures/Executor/ReferenceRepository.php
public function add($key, $object)
    {
        if ($this->repository->containsKey($key))
            throw new ReferenceExistsException();
        $this->repository->set($key, $object);
    }
public function add($key, $object)
    {
        if ($this->repository->containsKey($key))
            throw new ReferenceExistsException();
        $this->repository->set($key, $object);
    }
Add a reference identified by key

@param $key
@param $object
@return $this
@throws ReferenceExistsException if reference already exists identified by key