'Returns a list of roles assigned to a user for a tenant.'

def list_user_roles_on_project(self, tenant_id, user_id, **params):

    url = ('/tenants/%s/users/%s/roles' % (tenant_id, user_id))
    if params:
        url += ('?%s' % urllib.urlencode(params))
    (resp, body) = self.get(url)
    self.expected_success(200, resp.status)
    body = json.loads(body)
    return rest_client.ResponseBody(resp, body)
