Question about disable old url

[diegothucao]

Dear all mate,
I am working with this library and have a question about this.
First time I generate a url with streamKey as diegoCao using api Pili.publishURL and have url1.
After that I generate second url with same streamKey diegoCao and have url2.

So this time I have 2 urls, url1 and url2.
How can I disable url1, I mean this time I want only url2 is valid.

Thanks,
Diego