Nested jsonnet validators

The current validators do not work as nested validators, e.g.:

local test = import 'github.com/yugui/jsonnetunit/jsonnetunit/test.libsonnet';
local validator = import 'validator.libsonnet';

test.suite({
  test_nested_validator_fail: {
    local myvalidator = validator.new({
      first_level: validator.optional(
        validator.new({
          myint: validator.number,
        })
      )
    }),
    local value = { first_level: {} },
    actual: myvalidator._validationMessages(value),
    expect: ['field first_level.myint is required']
  },
})

scripts/jsonnet_test.sh libsonnet/utils/nested_validator_test.jsonnet
# libsonnet/utils/nested_validator_test.jsonnet
RUNTIME ERROR: Unexpected type object, expected function
	libsonnet/utils/validator.libsonnet:81:22-34	thunk <result> from <function <anonymous>>
	libsonnet/utils/validator.libsonnet:82:10-16	function <anonymous>
	libsonnet/utils/validator.libsonnet:16:36-60	thunk <failureMessage> from <function <anonymous>>
	libsonnet/utils/validator.libsonnet:17:16-30	function <anonymous>
	libsonnet/utils/validator.libsonnet:(6:5)-(25:6)	function <validateNested>
	libsonnet/utils/validator.libsonnet:32:7-45	function <anonymous>
	libsonnet/utils/nested_validator_test.jsonnet:15:13-47	object <anonymous>
	/Users/hercules/GitLab/runbooks/vendor/github.com/yugui/jsonnetunit/jsonnetunit/test.libsonnet:7:46-57	thunk from <object <anonymous>>
	/Users/hercules/GitLab/runbooks/vendor/github.com/yugui/jsonnetunit/jsonnetunit/std_matchers.libsonnet:4:14-20	object <anonymous>
	/Users/hercules/GitLab/runbooks/vendor/github.com/yugui/jsonnetunit/jsonnetunit/matcher.libsonnet:6:30-44	function <anonymous>
	/Users/hercules/GitLab/runbooks/vendor/github.com/yugui/jsonnetunit/jsonnetunit/test.libsonnet:34:11-49	thunk <failures> from <object <anonymous>>
	/Users/hercules/GitLab/runbooks/vendor/github.com/yugui/jsonnetunit/jsonnetunit/test.libsonnet:(31:22)-(35:6)
	/Users/hercules/GitLab/runbooks/vendor/github.com/yugui/jsonnetunit/jsonnetunit/test.libsonnet:36:19-27	thunk from <object <anonymous>>
	/Users/hercules/GitLab/runbooks/vendor/github.com/yugui/jsonnetunit/jsonnetunit/test.libsonnet:36:8-28	object <anonymous>
	Field "verify"
	During manifestation

# libsonnet/utils/nested_validator_test.jsonnet failed

Is it a typebug or typefeature? Is it bending jsonnet too much? 😄