code: public String getName(Object referenced) {
  		if (referenced == null)
  			throw new NullPointerException("referenced");
  		if (scopes.isEmpty())
  			return null;
  		
  		int size = scopes.size();
  		int i = size - 1;
  		while (i >= 0) {
  			Scope currentScope = scopes.get(i--);
  			for (Variable v : currentScope.variables()) {
  				if (v.referenced.equals(referenced))
  					return v.name;
  			}
  		}
  		return null;
  	}
docs: /* @Nullable