private function extractInclusions(array $params)
    {
        if (false === $this->issetNotEmpty(self::PARAM_INCLUSIONS, $params)) {
            if (true === $this->config->includeAllByDefault()) {
                $this->inclusions = ['*' => true];
            }
            return $this;
        }
        $inclusions = explode(',', $params[self::PARAM_INCLUSIONS]);
        foreach ($inclusions as $inclusion) {
            if (false !== stristr($inclusion, '.')) {
                throw RestException::invalidParamValue(self::PARAM_INCLUSIONS, sprintf('Inclusion via a relationship path, e.g. "%s" is currently not supported.', $inclusion));
            }
            $this->inclusions[$inclusion] = true;
        }
        return $this;
    }