ArangoDB: Collect syntax statement error when adding the sum function for an collection attribute

I am trying to add all the Amounts in the edge collection and also extract the days from the date attribute in the edge collection named Transaction.

However, I am getting error in the collect statement.

for d in Transaction 
        filter d._to == "Account/123" 
        COLLECT aggregate ct =count(d._id),
        aggregate totamnt=sum(d.Amount), 
        aggregate daysactive= count(distinct date_trunc(d.Time))
return distinct {"Incoming Accounts":length, "Days Active": daysactive}

If I understand what you want to achieve correctly, this is a query to achieve it:

FOR d IN Transaction
        FILTER d._to == "Account/123" 
        COLLECT AGGREGATE length = COUNT_UNIQUE(d._id), 
                          totamnt = SUM(d.Amount),
                          daysactive = COUNT_UNIQUE(DATE_TRUNC(d.Time, "day"))
        RETURN { 
            "Incoming Accounts": length , 
            "Days Active": LENGTH(daysactive), 
            "Total Amount": totamnt 
        }

Note: The distinct is not necessary, I include the total amount in the return value, and specified "day" as the unit to truncate the date to.

I tested this slightly adapted on a collection of mine and got sensible results.