__call__ (
        propertyMap,
        configKey,
        targetObject,
        )

Retrieve configKey for targetObject or return NOT_FOUND

The rule object is allowed to call any IConfigurable methods on the propertyMap that is requesting computation of this rule.

What an IRule must not do, however, is return different results over time for the same input parameters. If it cannot guarantee this algorithmically, it must cache its results keyed by the parameters it used, and not compute the results a second time.