ValidateCreateDocumentTypeCommand(CreateDocumentTypeCommand cmd) => from x in ValidateNonNull(cmd) from y in ValidateDocumentTypeName(x.Name) select cmd;
public Try <Validation <Error, DocumentTypeDto> > Execute(CreateDocumentTypeCommand cmd) => () => from x in ValidateCreateDocumentTypeCommand(cmd) let y = CreateDocumentTypeFrom(x) let z = repository.Create(y) select z.ToDocumentTypeDto();