protected function loadDataForPrefix($namespace, $prefix)
    {
        $this->failOnMissingNamespace($namespace);

        if (!isset($this->cachedData[$namespace])) {
            $this->cachedData[$namespace] = [];
        }

        if (!isset($this->cachedData[$namespace][$prefix])) {
            $this->cachedData[$namespace][$prefix] = [];
        }

        foreach ($this->addedData[$namespace] as $data) {

            if (isset($data[$prefix])) {
                $this->cachedData[$namespace][$prefix][] = $data[$prefix];
            }
        }

        return $this->cachedData[$namespace][$prefix];
    }