function getVersionForKey(tuples, key) {
  // TODO(nnaze): Move to util if useful elsewhere.

  const pair = googArray.find(tuples, function(pair) {
    return key == pair[0];
  });

  return pair && pair[1] || '';
}
@param {!Array<!Array<string>>} tuples Version tuples.
@param {string} key The key to look for.
@return {string} The version string of the given key, if present.
    Otherwise, the empty string.