Is there ability to add multiple roles via WP api?

Hello there,
I just downloaded this plugin and it looks great. I was wondering if you knew off hand if it would allow for multiple roles to be assigned to a user via the built in WP API? I am currently testing and playing around with using the following with python (at least the basics of what I am doing):

update = {'roles': payload[1]}
            r = requests.post(
                self.oauth2.base_url + query % id, json=update,
                headers={
                    'Authorization': 'Bearer %s' % self.oauth2session.access_token
                }
            )

Which allows to take the user current role and assign a new one, but I am hoping that I may be able to leave the base subscriber role and the also add 1 or more custom roles after setting them up with your plugin. Do you know if this is something I can accomplish?

Thanks!