constructor(props) {
    super(props);

    this._element = null;
    this._originalBodyPadding = null;
    this.getFocusableChildren = this.getFocusableChildren.bind(this);
    this.handleBackdropClick = this.handleBackdropClick.bind(this);
    this.handleBackdropMouseDown = this.handleBackdropMouseDown.bind(this);
    this.handleEscape = this.handleEscape.bind(this);
    this.handleStaticBackdropAnimation =
      this.handleStaticBackdropAnimation.bind(this);
    this.handleTab = this.handleTab.bind(this);
    this.onOpened = this.onOpened.bind(this);
    this.onClosed = this.onClosed.bind(this);
    this.manageFocusAfterClose = this.manageFocusAfterClose.bind(this);
    this.clearBackdropAnimationTimeout =
      this.clearBackdropAnimationTimeout.bind(this);
    this.trapFocus = this.trapFocus.bind(this);

    this.state = {
      isOpen: false,
      showStaticBackdropAnimation: false,
    };
  }
Unmounts the modal when modal is closed