nx, see the
section on specific markup, :ref:`ref-role`.


Sections
--------

Section headers (:duref:`ref &lt;sections&gt;`) are created by underlining (and
optionally overlining) the section title with a punctuation character, at least
as long as the text::

   =================
   This is a heading
   =================

Normally, there are no heading levels assigned to certain characters as the
structure is determined from the succession of headings.  However, for the
Python documentation, this conventio