final Collection<PageNode<? extends IsWidget>> pageNodes = pagesByRole.get(role);
if (pageNodes.size() == 1) {
return pageNodes.iterator().next();
}
else if (pageNodes.size() < 1) {
throw new MissingPageRoleException(role);
}
else {
throw new IllegalStateException("Role '" + role + "' is not unique multiple pages: " + pageNodes + " found");
}
}