function createArrowElement(arrowType) {
  var arrow = div();

  if (arrowType === 'round') {
    arrow.className = 'tippy-roundarrow';
    setInnerHTML(arrow, '<svg viewBox="0 0 18 7" xmlns="http://www.w3.org/2000/svg"><path d="M0 7s2.021-.015 5.253-4.218C6.584 1.051 7.797.007 9 0c1.203-.007 2.416 1.035 3.761 2.782C16.012 7.005 18 7 18 7H0z"/></svg>');
  } else {
    arrow.className = 'tippy-arrow';
  }

  return arrow;
}
Creates an arrow element and returns it