'Transform the following tree::
<node>
<section>
<title>
into ::
<node>
<title>
`node` is normally a document.'

def promote_title(self, node):

    assert (not (len(node) and isinstance(node[0], nodes.title)))
    (section, index) = self.candidate_index(node)
    if (index is None):
        return None
    node.attributes.update(section.attributes)
    node[:] = ((section[:1] + node[:index]) + section[1:])
    assert isinstance(node[0], nodes.title)
    return 1
