The Google style guide contains an excellent Python style guide. It includes conventions for readable docstring syntax that offers better guidance than PEP-257. For example:

def square_root(n):
"""Calculate the square root of a number.
Args:
n: the number to get the square root of.
Returns:
the square root of n.
Raises:
TypeError: if n is not a number.
ValueError: if n is negative.
"""
pass

I like to extend this to also include type information in the arguments, as described in this Sphinx documentation tutorial. For example:

def add_value(self, value):
"""Add a new value.
Args:
value (str): the value to add.
"""
pass