[iLemming]

Write a docstring for a function before you write the body of that function. Keep it short. Don't overthink it. At this point, it doesn't even have to be syntactically correct.

If, in a brief sentence, written in plain English (or any other language of your choice), you can't explain the idea, you need to "go back to the drawing board." Resist the urge writing it in a programming language before you can explain it in English.

When you're done writing the function, go back to the docstring, revise it; in some cases, you can even remove it.

The purpose of a docstring is to help humans to quickly scan the code and discern the meaning, the idea of the function without having to read its source. Like a trailer for a movie - it should give you the general idea, but not give away the implementation details.

Think about docstrings as "type annotations" for humans. We use types and type hints "to help the compiler understand our code better" because computers do not understand plain English, but very often, we have no empathy for fellow programmers.