[ic] How do I kill [data session source] ?

[Dave Barr]

(IC 4.6.5, Debian 2.2-17, MySQL 3.22, Perl 5.005-03)

Hi people...

I'm integrating some 'advanced' levels of affiliate control, ie 
changing the Coporate 'look & feel' on-the-fly by use of 
mv_pc=*affiliate* and called using
[data session source]. I checked the pdfs and developer.akopia.com 
but cannot find how to zero/blank/kill this data if called 
incorrectly...eg:

if..
   the affiliate does not exist
   the affiliate was spelled incorrectly
   the affiliate has been purged from the db

How do I reassign [data session source] to be the default of 0/blank etc?

The following (is just the first run) and works a treat:
<<SNIP>>
[if session source]
   [perl tables=affiliate interpolate=1]
     my $key = '[data session source]';
     $key =~ s/\s+//g;
     my $darkcol = tag_data('affiliate', 'darkcolour', $key);
     my $litecol = tag_data('affiliate', 'litecolour', $key);
     $Values->{darkcolour} = $darkcol;
     $Values->{litecolour} = $litecol;
     return;
   [/perl]
[else]
   [calc]
     $Values->{darkcolour} = "000099";
     $Values->{litecolour} = "3399FF";
     return;
   [/calc]
[/else][/if]
<</SNIP>>

So what I intend to do next is a whole slue of error checking, and if 
any errors are encountered basically blank the affiliate data and run 
with default, but, how do I do this?

Hope some of that made sense  :P
Thanks...
"D"