default R lessThan(V upper) {
    Objects.requireNonNull(upper, "upper");
    return Matchers.extract(this).applyAndCreateRoot(e -> Expressions.binaryCall(ComparableOperators.LESS_THAN, e, Expressions.constant(upper)));
  }
Checks that attribute is less than (but not equal to) {@code upper} (equivalent to {@code $this < upper}).
<p>Use {@link #atMost(Comparable)} for less <i>or equal</i> comparison</p>
criteria/common/src/org/immutables/criteria/matcher/ComparableMatcher.java