Using IN to decouple different partitions in the same rule

If data objects in an expression are different partitions of the same type, the expression might evaluate to "none".

For example:

MyMap ( Good<>Design , Best<>Design )

Good and Best are partitions of the same type, Design. A given Design could never be both a Good<>Design and a Best<>Design; therefore, the second argument of MyMap, Best<>Design, evaluates to "none".

To reference both the Good and Best partitions, use IN:

MyMap ( Good IN Design , Best IN Design )