docs: def help(self, taskname=None):
          """
          List tasks or provide help for specific task
          :param taskname: if supplied, help for this specific task is displayed.
              Otherwise, displays overview of available tasks.
          :return: None
          """
  
          if not taskname:
              print(inspect.getdoc(self._tasks))
              print()
              print('Available tasks:')
              print()
  
              for task in self.get_tasks():
                  self.print_task_help(task[1], task[0])
          else:
              try:
                  task = self.get_task(taskname)
                  self.print_task_help(task, task.__name__)
  
              except TaskNotFound:
                  print('Task "%s" not found! Use "ape help" to get usage information.' % taskname)