code: function formatString (string) {
      const separator = "\n";
      return Array.isArray(string) ?
          string.reduce((acc, line) => acc.concat(line.split(separator)), []) :
          string.split(separator);
  }
docs: Reformat passed arguments into an array of line string
  @param {String|Array<String>} string -
  @return {Array<String>}