code: def funnel(self, serie):
          
          serie_node = self.svg.serie(serie)
          fmt = lambda x: '%f %f' % x
          for i, poly in enumerate(serie.points):
              metadata = serie.metadata.get(i)
              val = self._format(serie, i)
  
              funnels = decorate(
                  self.svg, self.svg.node(serie_node['plot'], class_="funnels"),
                  metadata
              )
  
              alter(
                  self.svg.node(
                      funnels,
                      'polygon',
                      points=' '.join(map(fmt, map(self.view, poly))),
                      class_='funnel reactive tooltip-trigger'
                  ), metadata
              )
  
              # Poly center from label
              x, y = self.view((
                  self._center(self._x_pos[serie.index]),
                  sum([point[1] for point in poly]) / len(poly)
              ))
              self._tooltip_data(
                  funnels, val, x, y, 'centered', self._get_x_label(serie.index)
              )
              self._static_value(serie_node, val, x, y, metadata)
docs: Draw a funnel slice