code: def metatile_children_with_size(coord, metatile_zoom, nominal_zoom, tile_size):
      
  
      from tilequeue.tile import coord_children_subrange
      from tilequeue.tile import metatile_zoom_from_size
  
      assert tile_size >= 256
      assert tile_size <= 256 * (1 << metatile_zoom)
      assert _is_power_of_2(tile_size)
  
      # delta is how many zoom levels _lower_ we want the child tiles, based on
      # their tile size. 256px tiles are defined as being at nominal zoom, so
      # delta = 0 for them.
      delta = metatile_zoom_from_size(tile_size // 256)
  
      zoom = nominal_zoom - delta
  
      return list(coord_children_subrange(coord, zoom, zoom))
docs: Return a list of all the coords which are children of the input metatile
      at `coord` with zoom `metatile_zoom` (i.e: 0 for a single tile metatile,
      1 for 2x2, 2 for 4x4, etc...) with size `tile_size` corrected for the
      `nominal_zoom`.
  
      For example, in a single tile metatile, the `tile_size` must be 256 and the
      returned list contains only `coord`.
  
      For an 8x8 metatile (`metatile_zoom = 3`), requesting the 512px children
      would give a list of the 4x4 512px children at `coord.zoom + 2` with
      nominal zoom `nominal_zoom`.
  
      Correcting for nominal zoom means that some tiles may have coordinate zooms
      lower than they would otherwise be. For example, the 0/0/0 tile with
      metatile zoom 3 (8x8 256px tiles) would have 4x4 512px tiles at coordinate
      zoom 2 and nominal zoom 3. At nominal zoom 2, there would be 2x2 512px
      tiles at coordinate zoom 1.