Example fails while building doc

[eddiebergman]

Building the doc fails for example 40_advanced/example_single_configurations on the current development branch

Logs here

...
generating gallery for examples/40_advanced... [ 50%] example_debug_logging.py

Warning, treated as error:
/home/runner/work/auto-sklearn/auto-sklearn/examples/40_advanced/example_single_configuration.py failed to execute correctly: Traceback (most recent call last):
  File "/home/runner/work/auto-sklearn/auto-sklearn/examples/40_advanced/example_single_configuration.py", line 75, in <module>
    print(pipeline.named_steps)
AttributeError: 'NoneType' object has no attribute 'named_steps'
...

[eddiebergman]

Duplicate issue #1230, closing