def METHOD_NAME(self, panel: Any):
    if self.app:
        raise ValueError(
            "Extension already initialized for app, cannot add more" " panel"
        )
    self.panels.append(panel)
    panel.admin = self
    rule = f"/{panel.id}"
    endpoint = nav_id = panel.id
    abs_endpoint = f"admin.{endpoint}"
    if hasattr(panel, "get"):
        self.blueprint.add_url_rule(rule, endpoint, panel.get)
        self._panels_endpoints[abs_endpoint] = panel
    if hasattr(panel, "post"):
        post_endpoint = f"{endpoint}_post"
        self.blueprint.add_url_rule(
            rule, post_endpoint, panel.post, methods=["POST"]
        )
        self._panels_endpoints[f"admin.{post_endpoint}"] = panel
    panel.install_additional_rules(
        self.get_panel_url_rule_adder(panel, rule, endpoint)
    )
    nav = NavItem(
        "admin:panel",
        nav_id,
        title=panel.label,
        icon=panel.icon,
        endpoint=abs_endpoint,
    )
    self.nav_root.append(nav)
    self.nav_paths[abs_endpoint] = nav.path
    self.breadcrumb_items[panel] = BreadcrumbItem(
        label=panel.label, icon=panel.icon, url=Endpoint(abs_endpoint)
    )