docs: private String commaSeparate(Collection<String> strings)
      {
          StringBuilder buffer = new StringBuilder();
          Iterator<String> iterator = strings.iterator();
          while (iterator.hasNext())
          {
              String string = iterator.next();
              buffer.append(string);
              if (iterator.hasNext())
              {
                  buffer.append(", ");
              }
          }
          return buffer.toString();
      }