docs: def pixel_y_size(self, zoom):
          """
          Height of a pixel in SRID units at zoom level.
  
          - zoom: zoom level
          """
          validate_zoom(zoom)
          return round(
              (self.grid.top - self.grid.bottom) /
              (self.grid.shape.height * 2**zoom * self.tile_size),
              ROUND
          )