code: public void visit(final WebAppErrorPage webAppErrorPage) {
  		NullArgumentException.validateNotNull(webAppErrorPage,
  				"Web app error page");
  		//CHECKSTYLE:OFF
  		try {
  			webContainer.unregisterErrorPage(webAppErrorPage.getError(),
  					httpContext);
  		} catch (Exception ignore) {
  			LOG.warn("Unregistration exception. Skipping.", ignore);
  		}
  		//CHECKSTYLE:ON
  	}
docs: Unregisters error pages from web container.
  
  @throws NullArgumentException if error page is null
  @see WebAppVisitor#visit(WebAppErrorPage)