public async Task <OperationalResult> DeleteAsync(Operational <string> operational, CancellationToken cancellationToken = default)
{
var bookNo = operational.Parameter;
Expression <Func <Book, bool> > expression = p => p.No == bookNo;
var result = await _bookStore.DeleteAsync(expression, cancellationToken);
return(result ? OperationalResult.Ok() : OperationalResult.Failed(""));
}