@Override
  public @NotNull Set<String> getNamespacesByTagName(@NotNull String tagName, @NotNull XmlFile file) {
    Set<String> set = null;
    for (XmlSchemaProvider provider : XmlSchemaProvider.EP_NAME.getExtensionList()) {
      if (provider.isAvailable(file)) {
        if (set == null) {
          set = new HashSet<>();
        }
        set.addAll(provider.getAvailableNamespaces(file, tagName));
      }
    }
    return set == null ? Collections.emptySet() : set;
  }
@Override
  public @NotNull Set<String> getNamespacesByTagName(@NotNull String tagName, @NotNull XmlFile file)