code: async function getSubtitlesByHash (hash) {
    return request({
      method: 'GET',
      uri: SUBDB_API_URL,
      qs: {
        hash,
        action: 'download',
        language: 'en'
      },
      headers: {
        'User-Agent': 'SubDB/1.0 (subz-hero/0.1; https://github.com/BeLi4L/subz-hero)'
      }
    })
  }
docs: Get subtitles for the given hash.
  
  @param {string} hash - a hex string that identifies a file
  @returns {Promise<string>} the subtitles, formatted as .srt