docs: def strip_v2_elements(etree_obj):
      """In-place remove elements and attributes that are only valid in v2 types.
  
      Args:   etree_obj: ElementTree     ElementTree holding one of the DataONE API types
      that changed between v1 and v2.
  
      """
      if etree_obj.tag == v2_0_tag('logEntry'):
          strip_logEntry(etree_obj)
      elif etree_obj.tag == v2_0_tag('log'):
          strip_log(etree_obj)
      elif etree_obj.tag == v2_0_tag('node'):
          strip_node(etree_obj)
      elif etree_obj.tag == v2_0_tag('nodeList'):
          strip_node_list(etree_obj)
      elif etree_obj.tag == v2_0_tag('systemMetadata'):
          strip_system_metadata(etree_obj)
      else:
          raise ValueError('Unknown root element. tag="{}"'.format(etree_obj.tag))