function queryAssignedNodes(slotName = '', flatten = false) {
    return (protoOrDescriptor, 
    // tslint:disable-next-line:no-any decorator
    name) => {
        const descriptor = {
            get() {
                const selector = `slot${slotName ? `[name=${slotName}]` : ''}`;
                const slot = this.renderRoot.querySelector(selector);
                return slot && slot.assignedNodes({ flatten });
            },
            enumerable: true,
            configurable: true,
        };
        return (name !== undefined) ?
            legacyQuery(descriptor, protoOrDescriptor, name) :
            standardQuery(descriptor, protoOrDescriptor);
    };
}
A property decorator that converts a class property into a getter that
returns the `assignedNodes` of the given named `slot`. Note, the type of
this property should be annotated as `NodeListOf<HTMLElement>`.