code: def _CreateLineString(self, parent, coordinate_list):
      
      if not coordinate_list:
        return None
      linestring = ET.SubElement(parent, 'LineString')
      tessellate = ET.SubElement(linestring, 'tessellate')
      tessellate.text = '1'
      if len(coordinate_list[0]) == 3:
        altitude_mode = ET.SubElement(linestring, 'altitudeMode')
        altitude_mode.text = 'absolute'
      coordinates = ET.SubElement(linestring, 'coordinates')
      if len(coordinate_list[0]) == 3:
        coordinate_str_list = ['%f,%f,%f' % t for t in coordinate_list]
      else:
        coordinate_str_list = ['%f,%f' % t for t in coordinate_list]
      coordinates.text = ' '.join(coordinate_str_list)
      return linestring
docs: Create a KML LineString element.
  
      The points of the string are given in coordinate_list. Every element of
      coordinate_list should be one of a tuple (longitude, latitude) or a tuple
      (longitude, latitude, altitude).
  
      Args:
        parent: The parent ElementTree.Element instance.
        coordinate_list: The list of coordinates.
  
      Returns:
        The LineString ElementTree.Element instance or None if coordinate_list is
        empty.