code: def list_permissions(self, group_name=None, resource=None):
          
          self.project_service.set_auth(self._token_project)
          return self.project_service.list_permissions(group_name, resource)
docs: List permission sets associated filtering by group and/or resource.
  
          Args:
              group_name (string): Name of group.
              resource (intern.resource.boss.Resource): Identifies which data
                  model object to operate on.
  
          Returns:
              (list): List of permissions.
  
          Raises:
              requests.HTTPError on failure.