code: def delete_task_group(self, project, task_group_id, comment=None):
          
          route_values = {}
          if project is not None:
              route_values['project'] = self._serialize.url('project', project, 'str')
          if task_group_id is not None:
              route_values['taskGroupId'] = self._serialize.url('task_group_id', task_group_id, 'str')
          query_parameters = {}
          if comment is not None:
              query_parameters['comment'] = self._serialize.query('comment', comment, 'str')
          self._send(http_method='DELETE',
                     location_id='6c08ffbf-dbf1-4f9a-94e5-a1cbd47005e7',
                     version='5.1-preview.1',
                     route_values=route_values,
                     query_parameters=query_parameters)
docs: DeleteTaskGroup.
          [Preview API] Delete a task group.
          :param str project: Project ID or project name
          :param str task_group_id: Id of the task group to be deleted.
          :param str comment: Comments to delete.