code: function randomAlpha (n) {
    var alpha = "abcdefghijklmnopqrstuvwxyz";
    var res = "";
    for (var i = 0; i < n; i++) {
      res += alpha.charAt(Math.floor(Math.random() * alpha.length));
    }
    return res;
  }
docs: Generates a string of `n` random lowercase characters.
  
  @param {Number} n
  @return {String}