code: def slice(
              self, serie_node, node, radius, small_radius, angle, start_angle,
              center, val, i, metadata
      ):
          
          if angle == 2 * pi:
              angle = nearly_2pi
  
          if angle > 0:
              to = [
                  coord_abs_project(center, radius, start_angle),
                  coord_abs_project(center, radius, start_angle + angle),
                  coord_abs_project(center, small_radius, start_angle + angle),
                  coord_abs_project(center, small_radius, start_angle)
              ]
              rv = self.node(
                  node,
                  'path',
                  d='M%s A%s 0 %d 1 %s L%s A%s 0 %d 0 %s z' % (
                      to[0], coord_dual(radius), int(angle > pi), to[1], to[2],
                      coord_dual(small_radius), int(angle > pi), to[3]
                  ),
                  class_='slice reactive tooltip-trigger'
              )
          else:
              rv = None
          x, y = coord_diff(
              center,
              coord_project((radius + small_radius) / 2, start_angle + angle / 2)
          )
  
          self.graph._tooltip_data(
              node, val, x, y, "centered", self.graph._x_labels
              and self.graph._x_labels[i][0]
          )
          if angle >= 0.3:  # 0.3 radians is about 17 degrees
              self.graph._static_value(serie_node, val, x, y, metadata)
          return rv
docs: Draw a pie slice