anchor.diff:  	writeln(to_str(c));
   end;
   
  -function check(c: container; pattern: string): boolean;
  +function equal(c: container; pattern: string): boolean;
   begin
   	check := to_str(c) = pattern;
  +end;
  +
  +procedure check(c: container; pattern: string);
  +begin
  +	if equal(c, pattern) then
  +		writeln('Ok')
  +	else
  +		writeln('Foo');
   end;
   
   procedure test();
  
positive.code: 	m.insert(it, -3);
  	it.destroy();
  
  	if check(m, '1 2 -3 -2 -1 3 4 5') then
  		writeln('Ok')
  	else
  		writeln('Foo');
  
  	it := m.get_begin();
  	it.next();
  
negative.code: 	m.erase(it);
  	it.destroy();
  
  	check(m, '1 -2 -1 3 4 5');
  	
  	m2 := container.create();
  	while not m.empty() do
  