public static @Nullable String getUnboundNamespaceForPrefix(String prefix, XmlFile xmlFile, Set<String> namespaces) {
    final List<XmlSchemaProvider> providers = XmlSchemaProvider.getAvailableProviders(xmlFile);
    for (XmlSchemaProvider provider : providers) {
      for (String namespace : namespaces) {
        if (prefix.equals(provider.getDefaultPrefix(namespace, xmlFile))) {
          return namespace;
        }
      }
    }
    return null;
  }
public static @Nullable String getUnboundNamespaceForPrefix(String prefix, XmlFile xmlFile, Set<String> namespaces)