private static void associateNegations(PredicateType a, PredicateType b) {
        a.negatedType = b;
        b.negatedType = a;
    }
The predicate types that exists in Speedment. A predicate type must always
have a negated {@code PredicateType} that is the exact negation of itself.

@author  Per Minborg
@since   2.1.0
runtime-parent/runtime-field/src/main/java/com/speedment/runtime/field/predicate/PredicateType.java