[rules-users] "contains" operator for collections as facts?

Hi. I understand that the "contains" operator works as follows (from the drools manual): However, what if the fact itself is a collection and I want to know whether or not that collect contains an item? For example, say I had an ArrayList instance inserted as a fact in the rulebase and in one of my queries my predicate is to express that that ArrayList instance contains a certain object. Any ideas? Thanks! Raffi