How to use the n8n-core.createDeferredPromise function in n8n-core

async getPostExecutePromise(executionId: string): Promise {
		// Create the promise which will be resolved when the execution finished
		const waitPromise = await createDeferredPromise();

		if (this.activeExecutions[executionId] === undefined) {
			throw new Error(`There is no active execution with id "${executionId}".`);
		}

		this.activeExecutions[executionId].postExecutePromises.push(waitPromise);

		return waitPromise.promise();
	}