How can I check if an element still exists in the DOM?

<div id="parent">
  ...
  <div class="my-class"></div>
</div>

let parent = document.getElementById('parent');
let myElement = parent.getElementsByClassName('my-class')[0];
parent.remove();

function stillExists(element) {
   // check if element still exists in DOM
}

stillExists(myElement) // should be false