public Task <ILanguageServerExtension> CreateAsync(IPythonLanguageServer server, IReadOnlyDictionary <string, object> properties, CancellationToken cancellationToken) => throw new NotImplementedException();
 public Task <ILanguageServerExtension> CreateAsync(IPythonLanguageServer server, IReadOnlyDictionary <string, object> properties, CancellationToken cancellationToken)
 {
     return(Task.FromResult <ILanguageServerExtension>(new GetAllExtension((Server)server, properties)));
 }