Simplify trigger dag example (#6643)
Simplify trigger dag example (#6643)

* Simplify trigger dag example

* fix lint

* more lint

Co-authored-by: Christopher Wilcox <1a61e7a0041d068722f1c352424109b22f854ce0@google.com>
GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples