code: public String mkString(String start, String sep, String end) {
  		return mkString(start, sep, end, false);
  	}
docs: Returns a string representation of this {@link LazySeq}.
  The string result starts with the string <code>start</code> and ends with <code>end</code>,
  whereas <code>sep</code> is as separator string between the elements of this sequence.