public boolean equal(CPA someCpa) {
		if(cpa.length==someCpa.length()){
			for(int i=0; i<cpa.length; i++){
				if(cpa[i]==null && someCpa.getAssignment(i) !=null || cpa[i]!=null &&someCpa.getAssignment(i)==null )
					return false;
				if(cpa[i]==null && someCpa.getAssignment(i)==null)
					return true;
				if(!cpa[i].equal(someCpa.getAssignment(i)))
					return false;
			}
			return true;
		}
		return false;
	}