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name: python description: Always use this skill when writing or editing python code!

python

• Keep lines short and avoid horizontal alignment.
• isort and black (unless the project specifies otherwise).
  • Install them with pip if not already installed.
• Avoid try except Exception that swallows errors.
  • Prefer logging, re-raising it, or handling specific exceptions.
• Always add type hints to code; especially anything non-obvious.
  • Prefer | over Union[] and | None over Optional.
  • Run a type checker (e.g.: mypy) and fix all errors after writing the code.
• Whenever possible, extract logic out to staticmethods and classmethods.
• Don't return multiline statements; prefer assigning then returning.
• When using pydantic, prefer the new validators over the older @validator decorators.
  • e.g.: number: Annotated[int, AfterValidator(is_even)]
• Don't write useless getters and setters such as:

  Copy  def get_my_items(self) -> list[MyItem]:
      return self.my_items
  

  • Access the attributes directly.
• Don't setup logging in libraries; leave that to the application using the library.

dependencies

• Prefer adding dependencies without version constraints unless absolutely necessary.
• Never try except missing imports; assume users of our code will install all needed dependencies.
  • Add them to requirements.txt or equivalent.
  • Also, imports should always be at the top of the file.
• When installing packages for source code that's local, use pip install -e ./path.
  • So we don't confuse ourselves editing local code and running things from site-packages.