public function move(string $sourceInterface, string $sourceName, string $targetInterface, string $targetName)
    {
        $sourceIndex = $sourceInterface . '-' . $sourceName;
        if (! isset($this->container[$sourceIndex])) {
            throw $this->unbound($sourceIndex);
        }
        $targetIndex = $targetInterface . '-' . $targetName;
        $this->container[$targetIndex] = $this->container[$sourceIndex];
        unset($this->container[$sourceIndex]);
    }