samba - Apr 2012 - Howto find if a user has tickets

Hi
I need to test whether the user has tickets before running a script. 
ldbmodify needs this:
--kerberos=yes --krb5-ccache=$ccache
passing to it:

function setup {
ccache=$(klist -e | grep Ticket | cut -d ":" -f3)
if [ -z $ccache ]
then
echo "Please get a ticket. Try: kinit"
exit 1
fi

But maybe it's an old cache not destroyed.

Is there and easy way to do this?

Cheers,
Steve