code: def get_roles_by_type(self, role_type, view = None):
      
      return roles.get_roles_by_type(self._get_resource_root(), self.name,
          role_type, self._get_cluster_name(), view)
docs: Get all roles of a certain type in a service.
  
      @param role_type: Role type
      @param view: View to materialize ('full' or 'summary')
      @return: A list of ApiRole objects.