function insertIntoList(targetList, toInsert, offset) {
	  if (offset === targetList.count()) {
	    toInsert.forEach(function (c) {
	      targetList = targetList.push(c);
	    });
	  } else if (offset === 0) {
	    toInsert.reverse().forEach(function (c) {
	      targetList = targetList.unshift(c);
	    });
	  } else {
	    var head = targetList.slice(0, offset);
	    var tail = targetList.slice(offset);
	    targetList = head.concat(toInsert, tail).toList();
	  }
	  return targetList;
	}
Maintain persistence for target list when appending and prepending.