code: def tile_coords_to_bbox(cls, x, y, zoom):
          
          def tile_to_geocoords(x, y, zoom):
              n = 2. ** zoom
              lon = x / n * 360. - 180.
              lat = math.degrees(math.atan(math.sinh(math.pi * (1 - 2 * y / n))))
              return lat, lon
          north_west_corner =  tile_to_geocoords(x, y, zoom)
          south_east_corner = tile_to_geocoords(x+1, y+1, zoom)
          return north_west_corner[1], south_east_corner[0], south_east_corner[1], north_west_corner[0]
docs: Calculates the lon/lat estrema of the bounding box corresponding to specific tile coordinates. Output coodinates
          are in degrees and in the Mercator Projection (http://en.wikipedia.org/wiki/Mercator_projection)
  
          :param x: the x tile coordinates
          :param y: the y tile coordinates
          :param zoom: the zoom level
          :return: tuple with (lon_left, lat_bottom, lon_right, lat_top)