code: def _lines_only(shape):
      
  
      lines = _explode_lines(shape)
      if len(lines) == 1:
          return lines[0]
      else:
          return MultiLineString(lines)
docs: Extract the lines (LineString, MultiLineString) from any geometry. We
      expect the input to be mostly lines, such as the result of an intersection
      between a line and a polygon. The main idea is to remove points, and any
      other geometry which might throw a wrench in the works.