Document using a list for repeated arguments

[liamtoney]

Description of proposed changes

This seems like a reasonable place to put this info.

Reminders

• Run make format and make check to make sure the code follows the style guide.
• Add tests for new features or tests that would have caught the bug that you're fixing.
• Add new public functions/methods/classes to doc/api/index.rst.
• Write detailed docstrings for all functions/methods.
• If adding new functionality, add an example to docstrings or tutorials.

[weiji14]

Awesome! I can tell you're getting addicted to pull requests 😆