What are good ways to deal with repetitive content in docstrings? I have many functions that take 'standard' arguments, which have to be explained in the docstring, but it would be nice to write the relevant parts of the docstring only once, as this would be much easier to maintain and update. I naively tried the following:

arg_a = "a: a very common argument"

def test(a):
    '''
    Arguments:
    %s
    ''' % arg_a
    pass

But this does not work, because when I do help(test) I don't see the docstring. Is there a good way to do this?