code: public void append(StringConcatenation concat) {
  		if (concat != null)
  			appendSegments(segments.size(), concat.getSignificantContent(), concat.lineDelimiter);
  	}
docs: Append the contents of a given StringConcatenation to this sequence. Does nothing
  if the concatenation is <code>null</code>.
  
  @param concat
  the to-be-appended StringConcatenation.
  @since 2.11