code: function removeEvent(element, eventName, eventIndex) {
    if (element.__bunny_event_handlers !== undefined && element.__bunny_event_handlers.handlers[eventIndex] !== undefined) {
      element.removeEventListener(eventName, element.__bunny_event_handlers.handlers[eventIndex]);
      delete element.__bunny_event_handlers.handlers[eventIndex];
      // do not decrement counter, each new event handler should have next unique index
    }
    return null;
  }
docs: Remove event listener
  
  @param {HTMLElement} element
  @param {String} eventName
  @param {Number} eventIndex
  
  @returns {null}