code: def line(self, node, coords, close=False, **kwargs):
          
          line_len = len(coords)
          if len([c for c in coords if c[1] is not None]) < 2:
              return
          root = 'M%s L%s Z' if close else 'M%s L%s'
          origin_index = 0
          while origin_index < line_len and None in coords[origin_index]:
              origin_index += 1
          if origin_index == line_len:
              return
          if self.graph.horizontal:
              coord_format = lambda xy: '%f %f' % (xy[1], xy[0])
          else:
              coord_format = lambda xy: '%f %f' % xy
  
          origin = coord_format(coords[origin_index])
          line = ' '.join([
              coord_format(c) for c in coords[origin_index + 1:] if None not in c
          ])
          return self.node(node, 'path', d=root % (origin, line), **kwargs)
docs: Draw a svg line