code: public static Indentation tabs(final int level) {
          return level < TABS.length ? TABS[level > 0 ? level : 0] : new Indentation(1, '\t', level);
      }
docs: Returns an indentation of <code>level</code> tabs, increasing or decreasing
  by one tab at a time.
  
  @param level The number of tabs for this indentation.
  @return The indentation of <code>level</code> tabs.