template_method

id	behavioral/template_method
name	Template Method
aliases	hook-methods skeleton-algorithm
guide_url
problem	Fix an algorithm's skeleton while letting callers vary individual steps.
symptoms	same steps, different details framework calls your overrides setUp/tearDown-style hooks
verdict	prefer-alternative
caveats	Passing step callables as keyword arguments with defaults does the same job without inheritance, and composes better. Subclass hooks make sense at framework boundaries (unittest, socketserver) where the framework owns the loop and you own the steps.
stdlib_sightings	json.JSONEncoder.default unittest.TestCase.setUp socketserver.BaseRequestHandler.handle

Template Method

Fix the algorithm's spine, vary its steps. Verdict: prefer an alternative — pass the steps as callables; subclass hooks belong at framework boundaries that hand them to you.

Where	What
pattern/	The importable code: Skeleton, keep_all, discard
docs/	Fundamentals · Implementation guide · External examples
examples/report_pipeline/	Mini-project: sales reports built on pattern/
tests/	Behavioral tests for the pattern and the mini-project

uv run python -m patterns.behavioral.template_method.examples.report_pipeline.main