docs: public Boolean isInside(DensityGrid dg)
  	{
  		Iterator<DensityGrid> dgNeighbourhood = dg.getNeighbours().iterator();
  		
  		while(dgNeighbourhood.hasNext())
  		{
  			DensityGrid dgprime = dgNeighbourhood.next();
  			if(!this.grids.containsKey(dgprime))
  			{
  				return false;
  			}
  		}
  		
  		return true;
  	}