whole_func_string: function directoriesUnder (rootDir) {
    return directoryContents(
      rootDir,
      stats => stats.isDirectory(),
      (path, stats) => path
    )
  }
func_code_string: function directoriesUnder (rootDir) {
    return directoryContents(
      rootDir,
      stats => stats.isDirectory(),
      (path, stats) => path
    )
  }
func_documentation_string: collect