YamlFileLoader::validate

private YamlFileLoader::validate($content, $file)

private function validate($content, $file) 
 {
  if (null === $content) {
    return $content;
  }

  if (!is_array($content)) {
    throw new InvalidArgumentException(sprintf('The service file "%s" is not valid. It should contain an array. Check your YAML syntax.', $file));
  }

  if ($invalid_keys = array_diff_key($content, array('parameters' => 1, 'services' => 1))) {
    throw new InvalidArgumentException(sprintf('The service file "%s" is not valid: it contains invalid keys %s. Services have to be added under "services" and Parameters under "parameters".', $file, $invalid_keys));
  }

  return $content;
}