Test for unification in Oz

Question

What I want to do is, test if a certain expression unifies with another in Oz.

For example, I want to do something like this:

fun {UnifyP A B}
  ...
end

that can return true when A can be unified to B and false else.

I want to use it to do a specific pattern matching (i.e. filter lists by a specific pattern).

Thank you for your answers.