code: def _points(self, x_pos):
          
          for serie in self.all_series:
              serie.points = [(x_pos[i], v) for i, v in enumerate(serie.values)]
              if serie.points and self.interpolate:
                  serie.interpolated = self._interpolate(x_pos, serie.values)
              else:
                  serie.interpolated = []
docs: Convert given data values into drawable points (x, y)
          and interpolated points if interpolate option is specified