Serialize without an element node.

def serialize_text_node(self, elt, sw, pyobj):
        '''Serialize without an element node.
        '''
        textNode = None
        if pyobj is not None:
            text = self.get_formatted_content(pyobj)
            if type(text) not in _stringtypes:
                raise TypeError, 'pyobj must be a formatted string'

            textNode = elt.createAppendTextNode(text)

        return textNode