multiple select in treeview

[Dave Reed <dreed capital edu>]

I'm trying to set up the multiple select mode in a treeview (containing
liststore in this case) in gtk2 so that I can just click once on the
row and it will select the row and leave the other rows that are
already selected as is (i.e., for reconciling a bank account, I don't
want to have to press control and mouse click on each row). If I click
on a selected row, it should just unselect that row.

Is there a way to do this (i.e. have it work as if control was being
held down for each click)? I'm using pygtk but I doubt that affects
this.

Thanks,
Dave