get);
  }

  // add arrow to heading
  function addArrow(heading) {
    // add arrow button
    const arrow = document.createElement("button");
    arrow.innerHTML = document.querySelector(".icon_angle_down").innerHTML;
    arrow.classList.add("icon_button", "accordion_arrow");
    heading.insertBefore(arrow, heading.firstChild);

    // attach click listener to heading and button
    heading.addEventListener("click", onHeadingClick);
    arrow.addEventListener("click", onArrowClick);
  }

  // determine if