Docs: Improve docstrings

[Andy Nowacki]

Docstrings of public functions must be more comprehensive. Each should give a function signature, describe what the function does, specify what all the arguments are, and document the output. Most do not.

Please update the docstrings accordingly.

[Charlotte Haley]

See commit. Thanks.

[Andy Nowacki]

Thanks—this addresses my point and this issue can be closed.