code: @Override
  	public Collection<Node> check(final Collection<Node> nodes)  {
  		Assert.notNull(nodes, "nodes is null!");
  		this.nodes = nodes;
  		result = new LinkedHashSet<Node>();
  		String value = specifier.getValue();
  
  		if ("nth-child".equals(value))
  			addNthChild(false);
  		else if ("nth-last-child".equals(value))
  			addNthLastChild(false);
  		else if ("nth-of-type".equals(value))
  			addNthChild(true);
  		else if ("nth-last-of-type".equals(value))
  			addNthLastChild(false);
  		else
  			throw new RuntimeException("Unknown pseudo nth class: " + value);
  
  		return result;
  	}
docs: {@inheritDoc}