Here's my script: 

```
public PlainBrgDataSummaryComplete SummaryComputationPerTransSQLite(long    ProgramID)
{
    PlainBrgDataSummaryComplete result = new  PlainBrgDataSummaryComplete();
    DataSet dataSet = GetPlainBrgDataSQLite(ProgramID);

    var abcde  = dataSet.Tables["dataBridge"]
        .AsEnumerable()
        //.Where(a => Convert.ToDateTime(a["reportingDate"].ToString()) >= startOfWeek1 && Convert.ToDateTime(a["reportingDate"].ToString()) < endOfWeek1.AddDays(1))
       .GroupBy(a => 1)
        .Select(d =>
            new PlainBrgDataSummaryTrans
            {
                transactionWk6 = d.Sum(a => a.Field<double?>("TranCount"))

            }
        ).FirstOrDefault();

    result.totaltransaction = new PlainBrgDataSummaryTrans
    {
        transactionWk6 = abcde;
    };

    return result;
}

```

I'm getting the error - Cannot convert source type to `System.Nullable<double>`. Specifically on the part `transactionWk6 = abcde`;