Doubt over doc strings

Currently I’m working on some physics formulas. I’m writing code for the formulas and planning to create a small scale library in python. While using doc strings I have a confusion that which things are necessary to be added in the doc strings. Like error handling,formula rules,usage, limitations and so on. Give a example like, we are calculating the BMI of a person. I need your valuable suggestions. Thank you

docstrings are the way to write inline documentation for other developers and ourself.

write about the logics, arguments, datetypes, description etc, so that any other developer ( it may be you, in future) can understand why the code/function/class is written there and its usage.

https://www.datacamp.com/tutorial/docstrings-python

check here for some details on the same.

Thanks for the valuable info