if (variable instanceof MethodArgument) { return variable; } else { return null; }
return null;
	public Variable peek() {		int n = stack.size();		// This deals with cases where there are excessive phis (unpruned SSA)		if (n <= 0) {			if (variable instanceof MethodArgument) {				return variable;			} else {				return null;			}		}		Variable var = (Variable) stack.get(n - 1);		return var;	}