code: def copy_node(ret, element, msg):
          '''copy_node
  
          High-level api: Copy element as a node without its children and put it
          as a child of ret.
  
          Parameters
          ----------
  
          element : `Element`
              A node in a model tree.
  
          msg : `str`
              Message to be added.
  
          ret : `Element`
              A node in self.tree.
  
          Returns
          -------
  
          None
              Nothing returns.
          '''
          sub_element = etree.SubElement(ret, element.tag, attrib=element.attrib)
          ModelDiff.process_attrib(sub_element, msg)
          return sub_elemenf copy_node(ret, element, msg):
          '''copy_node
  
          High-level api: Copy element as a node without its children and put it
          as a child of ret.
  
          Parameters
          ----------
  
          element : `Element`
              A node in a model tree.
  
          msg : `str`
              Message to be added.
  
          ret : `Element`
              A node in self.tree.
  
          Returns
          -------
  
          None
              Nothing returns.
          '''
          sub_element = etree.SubElement(ret, element.tag, attrib=element.attrib)
          ModelDiff.process_attrib(sub_element, msg)
          return sub_element
docs: copy_node
  
          High-level api: Copy element as a node without its children and put it
          as a child of ret.
  
          Parameters
          ----------
  
          element : `Element`
              A node in a model tree.
  
          msg : `str`
              Message to be added.
  
          ret : `Element`
              A node in self.tree.
  
          Returns
          -------
  
          None
              Nothing returns.