public function loadServicesConfig()
    {
        $configPath = $this->serviceConfigPath;

        if (!file_exists($configPath)) {
            throw new InvalidArgumentException(
                sprintf(
                    "Service config file '%s' doesn`t exists",
                    $configPath
                )
            );
        }

        $config = json_decode(file_get_contents($configPath), true);

        if (!is_array($config)) {
            throw new RuntimeException('Empty credentials config');
        }

        $this->serviceConfig = $config;

        return $this;
    }