function getCssKeyframeDurationStyle(duration) {
  return [ANIMATION_DURATION_PROP, duration + 's'];
}
@ngdoc function
@name pascalprecht.translate.$translateProvider#use
@methodOf pascalprecht.translate.$translateProvider

@description
Set which translation table to use for translation by given language key. When
trying to 'use' a language which isn't provided, it'll throw an error.

You actually don't have to use this method since `$translateProvider#preferredLanguage`
does the job too.

@param {string} langKey A language key.