@Override
	public void setBloc(BlocService b, int i, int j) {
		if(!(0<=i && i<super.getNombreColonnes() && 0<=j && j<super.getNombreLignes()))
			throw new PreConditionError("unboud i or j");
		checkInvariants();
		super.setBloc(b, i, j);
		checkInvariants();
		if(!(super.getBloc(i, j)==b))
			throw new PostConditionError("getBloc(setBloc(T,b,i,j),i,j)!=b");
	}