code: public ExternalID getEpisodeExternalID(int tvID, int seasonNumber, int episodeNumber, String language) throws MovieDbException {
          return tmdbEpisodes.getEpisodeExternalID(tvID, seasonNumber, episodeNumber, language);
      }
docs: Get the external ids for a TV episode by comabination of a season and
  episode number.
  
  @param tvID tvID
  @param seasonNumber seasonNumber
  @param episodeNumber episodeNumber
  @param language language
  @return
  @throws MovieDbException exception