Hello tries to perform a test of a function, but receives this related error.

 TypeError: Cannot read properties of undefined (reading 'setFocus')

      81 |     this.lastFocusableElement = this.focusableElements[this.focusableElements.length - 1];
      82 |
    > 83 |     this.firstFocusableElement.setFocus();
         |                                        ^
      84 |   }
      85 |
      86 |   private clearFocusableElements(): void {

      at HTMLElement.setFocus (packages/modal/src/modal.ts:83:40)
      at HTMLElement.open (packages/modal/src/modal.ts:63:10)
      at Object.<anonymous> (packages/modal/src/modal.test.ts:102:14)

My Function

 private setFocus(): void {
    this.clearFocusableElements();
    this.findFocusableElements(this.querySelectorAll('*'));
    this.firstFocusableElement =
    this.modalElement.querySelector('.modal-close');
    this.lastFocusableElement = this.focusableElements[this.focusableElements.length - 1];
    this.firstFocusableElement.setFocus();
  }