code: def setattr(self, key, value):
          u
          if key == 'text':
              self._xml.text = str(value)
          else:
              self._xml.set(key, str(value))
docs: u"""Sets an attribute on a node.
  
          >>> xml = etree.Element('root')
          >>> Node(xml).setattr('text', 'text2')
          >>> Node(xml).getattr('text')
          'text2'
          >>> Node(xml).setattr('attr', 'val')
          >>> Node(xml).getattr('attr')
          'val'