anchor.diff:  		local_link := link.create(data);
   		if p.equal(m_end) and empty() then
   		begin
  -			local_link.setNext(m_end.getLink());
  -			m_end.getLink().setPrev(local_link);
  +			local_link.set_next(m_end.get_link());
  +			m_end.get_link().set_prev(local_link);
   			m_begin.prev();
   			p.prev();
   			exit();
  
positive.code: 
  		if p.equal(m_begin) then
  		begin
  			local_link.setNext(m_begin.getLink());
  			m_begin.getLink().setPrev(local_link);
  			m_begin.prev();
  			p.prev();
  		end
  		else
  		begin
  			local_link.setNext(p.getLink());
  			local_link.setPrev(p.getLink().m_prev);
  			p.getLink().m_prev.setNext(local_link);
  			p.getLink().setPrev(local_link);
  			p.prev();
  		end;
  	end;
  
negative.code: 		equal := m_link = other.m_link;
  	end;
  
  	function iterator.get_link(): link;
  	begin
  		get_link := m_link;
  	end;
  
  	constructor container.create();
  