_do_document(self, node) -> None
        Process a document node. documentOrder holds whether the document
        element has been encountered such that PIs/comments can be written
        as specified.

def _do_document(self, node):
        '''_do_document(self, node) -> None
        Process a document node. documentOrder holds whether the document
        element has been encountered such that PIs/comments can be written
        as specified.'''

        self.documentOrder = _LesserElement
        for child in node.childNodes:
            if child.nodeType == Node.ELEMENT_NODE:
                self.documentOrder = _Element        # At document element
                self._do_element(child)
                self.documentOrder = _GreaterElement # After document element
            elif child.nodeType == Node.PROCESSING_INSTRUCTION_NODE:
                self._do_pi(child)
            elif child.nodeType == Node.COMMENT_NODE:
                self._do_comment(child)
            elif child.nodeType == Node.DOCUMENT_TYPE_NODE:
                pass
            else:
                raise TypeError, str(child)