code: func (index *ClusteringIndex) Range(topLeft Point, bottomRight Point) []Point {
  	dist := distance(topLeft, bottomRight)
  
  	if dist < streetLevel {
  		return index.streetLevel.Range(topLeft, bottomRight)
  	} else if dist < cityLevel {
  		return index.cityLevel.Range(topLeft, bottomRight)
  	} else {
  		return index.worldLevel.Range(topLeft, bottomRight)
  	}
  }
docs: // Range returns points or count points depending on the size of the topLeft and bottomRight range.