public async Task <ActionResult <object> > List([FromQuery] string clientName)
        {
            var releases = BillingMock.GetBillings();

            if (!string.IsNullOrEmpty(clientName))
            {
                releases = releases.Where(x => x.Client.Contains(clientName, StringComparison.OrdinalIgnoreCase)).ToList();
            }

            return(await Task.FromResult(releases));
        }
        public async Task <ActionResult <object> > Get(int id)
        {
            var entity = BillingMock.GetBillings().FirstOrDefault(x => x.Id == id);

            return(await Task.FromResult(entity));
        }