@Nullable
  private XmlNSDescriptorImpl tryGetOrCreateDescriptor(final FileKind kind) {
    CachedValue<XmlNSDescriptorImpl> result = myDescriptorsMap.get(kind);
    if (result == null) {
      result = CachedValuesManager.getManager(myProject).createCachedValue(
        () -> CachedValueProvider.Result.create(doCreateDescriptor(kind), PsiModificationTracker.MODIFICATION_COUNT), false);
      myDescriptorsMap.put(kind, result);
    }
    return result.getValue();
  }
@Nullable
  private XmlNSDescriptorImpl tryGetOrCreateDescriptor(final FileKind kind)