code: def get_node_text(self, node):
          
          text_children = [n.nodeValue for n in self.get_node_children(node)
                           if n.nodeType == xml.dom.Node.TEXT_NODE]
          if text_children:
              return u''.join(text_children)
          else:
              return None
docs: Return contatenated value of all text node children of this element