Looks like you’ve got a working solution here, but I’d also like to chime in to say that you can sort by multiple columns in an app-tables.table.search(...) operation.
This code will sort by col1 in descending order, and rows that have the same value for col1 will be sorted by col2 in ascending order:
x = app_tables.my_table.search(tables.order_by('col1', ascending=False),
tables.order_by('col2'))