code: function replaceUnderscores(string) {
    if (typeof string === "string" || string instanceof String) {
      return string.replace(/_/g, " ");
    }
    return string;
  }
docs: Replace all underscores in the string with spaces. If the argument is not a string, return it unchanged.
  @param  {} string The string to replace. If the argument is not a string, does nothing.
  @return {} The argument with all underscores replaced with spaces. If the argument is not a string, returns the argument unchanged.