How can I use a code checker to check my Python code?

There are a number of tools and online services that you can use to check your Python code for errors and style violations. Here are some popular options:

1. PyLint: a popular tool that checks your Python code for errors, style violations, and more.
2. Flake8: a command-line tool that checks Python programs for style violations and other errors.
3. Black: a code formatter that reformats your Python code to make it more readable and consistent.
4. mypy: a static type checker that helps you find bugs and type errors in your Python code.
5. Pyright: a fast static type checker for Python that also provides code intelligence features like auto-completion and type inference.

You can use these tools in a variety of ways - some are command-line tools that you use on your local machine, while others are integrated into text editors or other development environments. To get started, you can typically install these tools using pip, the Python package manager.

Note that while code checkers can be helpful, they are not foolproof, and it’s still important to test your code thoroughly using unit tests and other techniques.