public static Inclusion getInclusionOperand(FieldPredicate<?> p) {
        return Cast.castOrFail(p, HasInclusion.class).getInclusion();
    }
Returns the {@link Inclusion} operand of the specified
{@link FieldPredicate}, throwing an exception if it doesn't exist. The
operand may however be {@code null}.

@param p  the predicate
@return   the operand
runtime-parent/runtime-field/src/main/java/com/speedment/runtime/field/util/PredicateOperandUtil.java