Multi-line description of a parameter description in python docstring

Good research effort from the Original Poster. It is a surprise that the
canonical sphinx documentation does not give a multi-line example on params, despite the fact that multi-line document is inevitable due to the
79-character guideline in PEP8.

In practice, considering that your parameter name itself is typically a word or even longer snake_case_words, prefixed by the already lenghty <4 or 8+ spaces> :param, it would be wise to make the next line indent for just one level (i.e. 4 spaces), which matches the “hanging indents” style metioned in
PEP 8.

class Foo(object):
    def f(a, bionic_beaver, cosmic_cuttlefish):
        """ Does something.

        :param a: something simple
        :param bionic_beaver: well, it's not something simple, 
            so it may require more than eighty chars,
            and more, and more
        :param cosmic_cuttlefish:
            Or you can just put all your multi-line sentences
            to start with SAME indentation.
        """

PS: You can see it in action in, for example,
here.
Sphinx can pick up those docstrings and generates
docs without any issue.