code: func NewPointFromGeoHashInt64(hash int64, bits int) *Point {
  	west, east, south, north := geoHashInt2ranges(hash, bits)
  	return NewPoint((west+east)/2.0, (north+south)/2.0)
  }
docs: // NewPointFromGeoHashInt64 creates a new point at the center of the
  // integer version of a geohash range. bits indicates the precision of the hash.