ModulusChecking.Models.BankAccountDetails.ExceptionSevenPreprocessing C# (CSharp) Method

        private IList<ModulusWeightMapping> ExceptionSevenPreprocessing(IList<ModulusWeightMapping> mappings)
        {
            if (mappings.First().Exception != 7) return mappings;
            if (AccountNumber.IntegerAt(6) != 9) return mappings;

            return mappings.Select((m, index) => index == 0 ? ZeroiseUtoB(m) : m).ToList();
        }