Can Sphinx napoleon document function returning multiple arguments?

Python only returns a single object. If you call

serv,msg = foo(myinput)

Then you are explicitly expanding the expression_list tuple which is generated when the function returns with this code

return servers,msg

You docstring should read some thing like this (with the Napoleon Google Style)

"""
one line summary

longer explanation

Args:
    a (int): parameter description

Returns:
    (tuple): tuple containing:

        servers(list) servers to use
        msg (str): logging message string 
"""

Or with the Napoleon NumPy style:

"""
one line summary

longer explanation

Parameters
----------
a : int
    parameter description

Returns
-------
servers : list
    servers to use
msg : str
    logging message string 
"""

Have a look at the python docs for return and perhaps expression_list