For some reason they chose to put the concept which is hardest to understand on the front page. 'is foo' is showing how to define and use a custom condition, th

For some reason they chose to put the concept which is hardest to understand on the front page. 'is foo' is showing how to define and use a custom condition, the conditions in the rest of the documentation are easy to understand and make sense to me. The only way I could see me struggle with this would be to piece together a large call graph in my head. I can understand why the author says that Airflow is better suited for this case because you get a visualization.