code: def geoocoords_to_tile_coords(cls, lon, lat, zoom):
          
          n = 2.0 ** zoom
          x = int((lon + 180.0) / 360.0 * n)
          y = int((1.0 - math.log(math.tan(math.radians(lat)) + (1 / math.cos(math.radians(lat)))) / math.pi) / 2.0 * n)
          return x, y
docs: Calculates the tile numbers corresponding to the specified geocoordinates at the specified zoom level
          Coordinates shall be provided in degrees and using the Mercator Projection (http://en.wikipedia.org/wiki/Mercator_projection)
  
          :param lon: longitude
          :type lon: int or float
          :param lat: latitude
          :type lat: int or float
          :param zoom: zoom level
          :type zoom: int
          :return: a tuple (x, y) containing the tile-coordinates