code: public StringBuilder appendTo(StringBuilder builder, Iterable<? extends Entry<?, ? extends Collection<?>>> entries) {
  		try {
  			appendTo((Appendable) builder, entries);
  		} catch (IOException impossible) {
  			throw new AssertionError(impossible);
  		}
  		return builder;
  	}
docs: Appends the string representation of each entry in {@code entries}, using the previously configured separator and
  key-value separator, to {@code builder}. Identical to {@link #appendTo(Appendable, Iterable)}, except that it
  does not throw {@link IOException}.