How can I use Sphinx' Autodoc-extension for private methods?

I am using Sphinx for documenting my python project. I have the autodoc extension enabled and have the following in my docs.

.. autoclass:: ClassName    :members:

The problem is, it only documents the non-private methods in the class. How do I include the private methods too?

How does Sphinx Autodoc work?

autodoc provides several directives that are versions of the usual py:module , py:class and so forth. On parsing time, they import the corresponding module and extract the docstring of the given objects, inserting them into the page source under a suitable py:module , py:class etc. directive.

if you are using sphinx 1.1 or above, from the sphinx documentation site at http://www.sphinx-doc.org/en/master/ext/autodoc.html,