Use the PREV method
iteratively to traverse the hash object and return the data items
in reverse key order.
The FIRST method returns
the first data item in the hash object. The LAST method returns the
last data item in the hash object.
You can use the NEXT
method to return the next data item in the hash object.
Note: The PREV method sets the
data variable to the value of the data item so that it is available
for use after the method call.