code: def _int2coord(x, y, dim):
      
      assert dim >= 1
      assert x < dim
      assert y < dim
  
      lng = x / dim * 360 - 180
      lat = y / dim * 180 - 90
  
      return lng, lat
docs: Convert x, y values in dim x dim-grid coordinate system into lng, lat values.
  
      Parameters:
          x: int        x value of point [0, dim); corresponds to longitude
          y: int        y value of point [0, dim); corresponds to latitude
          dim: int      Number of coding points each x, y value can take.
                        Corresponds to 2^level of the hilbert curve.
  
      Returns:
          Tuple[float, float]: (lng, lat)
              lng    longitude value of coordinate [-180.0, 180.0]; corresponds to X axis
              lat    latitude value of coordinate [-90.0, 90.0]; corresponds to Y axis