private function parseDefinitions($content)
    {
        if (!isset($content['services'])) {
            return [];
        }

        if (!is_array($content['services'])) {
            throw new InvalidArgumentException(sprintf('The "services" key should contain an array in %s. Check your YAML syntax.', $this->fileName));
        }

        $definitions = [];

        foreach ($content['services'] as $id => $service) {
            $definitions[$id] = $this->parseDefinition($id, $service);
        }

        return $definitions;
    }