Problem with custom certificate authority

[WarinSitavarin]

I start to demonstrate and learning of JITP from this sample. It's perfect sample but I have a 1 question that Can I attach my root ca for JITP connection?

In iot_client_simulation.py

I do it many times. it doesn't work with my root ca. but it works on Amazon Root CA 1.
Does it have any way to connection with custom root ca?