How to use the stone.ir.Struct function in stone

def test_api_namespace(self):
        ns = ApiNamespace('files')
        a1 = Struct('A1', None, ns)
        a1.set_attributes(None, [StructField('f1', Boolean(), None, None)])
        a2 = Struct('A2', None, ns)
        a2.set_attributes(None, [StructField('f2', Boolean(), None, None)])
        l1 = List(a1)
        s = String()
        route = ApiRoute('test/route', 1, None)
        route.set_attributes(None, None, l1, a2, s, None)
        ns.add_route(route)

        # Test that only user-defined types are returned.
        route_io = ns.get_route_io_data_types()
        self.assertIn(a1, route_io)
        self.assertIn(a2, route_io)
        self.assertNotIn(l1, route_io)
        self.assertNotIn(s, route_io)

def test_api_namespace(self):
        ns = ApiNamespace('files')
        a1 = Struct('A1', None, ns)
        a1.set_attributes(None, [StructField('f1', Boolean(), None, None)])
        a2 = Struct('A2', None, ns)
        a2.set_attributes(None, [StructField('f2', Boolean(), None, None)])
        l1 = List(a1)
        s = String()
        route = ApiRoute('test/route', 1, None)
        route.set_attributes(None, None, l1, a2, s, None)
        ns.add_route(route)

        # Test that only user-defined types are returned.
        route_io = ns.get_route_io_data_types()
        self.assertIn(a1, route_io)
        self.assertIn(a2, route_io)
        self.assertNotIn(l1, route_io)
        self.assertNotIn(s, route_io)

def test_struct_with_custom_annotations(self):
        # type: () -> None
        ns = ApiNamespace('files')
        annotation_type = AnnotationType('MyAnnotationType', ns, None, [
            AnnotationTypeParam('test_param', Int32(), None, False, None, None)
        ])
        ns.add_annotation_type(annotation_type)
        annotation = CustomAnnotation('MyAnnotation', ns, None, 'MyAnnotationType',
            None, [], {'test_param': 42})
        annotation.set_attributes(annotation_type)
        ns.add_annotation(annotation)
        struct = Struct('MyStruct', ns, None)
        struct.set_attributes(None, [
            StructField('annotated_field', Int32(), None, None),
            StructField('unannotated_field', Int32(), None, None),
        ])
        struct.fields[0].set_annotations([annotation])

        result = self._evaluate_struct(ns, struct)

        expected = textwrap.dedent('''\
            class MyStruct(bb.Struct):

                __slots__ = [
                    '_annotated_field_value',
                    '_annotated_field_present',
                    '_unannotated_field_value',
                    '_unannotated_field_present',

'quota': AstExampleField(
                            None,
                            None,
                            None,
                            'quota',
                            None)}))
        self.assertEqual(
            "Bad example for field 'quota': null is not a valid integer",
            cm.exception.msg)

        self.assertTrue(quota_info._has_example('default'))

        quota_info.nullable = True

        # test for structs within structs
        account_info = Struct(
            'AccountInfo',
            None,
            ns,
        )
        account_info.set_attributes(
            "Information about an account.",
            [
                StructField('account_id', String(), 'Unique identifier for account.', None),
                StructField('quota_info', quota_info, 'Quota', None)
            ],
        )

        account_info._add_example(
            AstExample(
                path=None,
                lineno=None,

def _make_namespace_with_alias():
    # type: (...) -> ApiNamespace
    ns = ApiNamespace('ns_with_alias')

    struct1 = Struct(name='Struct1', namespace=ns, ast_node=None)
    struct1.set_attributes(None, [StructField('f1', Boolean(), None, None)])
    ns.add_data_type(struct1)

    alias = Alias(name='AliasToStruct1', namespace=ns, ast_node=None)
    alias.set_attributes(doc=None, data_type=struct1)
    ns.add_alias(alias)

    str_type = String(min_length=3)
    str_alias = Alias(name='NotUserDefinedAlias', namespace=ns, ast_node=None)
    str_alias.set_attributes(doc=None, data_type=str_type)
    ns.add_alias(str_alias)

    return ns

def _make_namespace_with_many_structs():
    # type: (...) -> ApiNamespace
    ns = ApiNamespace('ns_with_many_structs')

    struct1 = Struct(name='Struct1', namespace=ns, ast_node=None)
    struct1.set_attributes(None, [StructField('f1', Boolean(), None, None)])
    ns.add_data_type(struct1)

    struct2 = Struct(name='Struct2', namespace=ns, ast_node=None)
    struct2.set_attributes(
        doc=None,
        fields=[
            StructField('f2', List(UInt64()), None, None),
            StructField('f3', Timestamp(ISO_8601_FORMAT), None, None),
            StructField('f4', Map(String(), UInt64()), None, None)
        ]
    )
    ns.add_data_type(struct2)

    return ns

def _make_namespace_with_many_structs():
    # type: (...) -> ApiNamespace
    ns = ApiNamespace('ns_with_many_structs')

    struct1 = Struct(name='Struct1', namespace=ns, ast_node=None)
    struct1.set_attributes(None, [StructField('f1', Boolean(), None, None)])
    ns.add_data_type(struct1)

    struct2 = Struct(name='Struct2', namespace=ns, ast_node=None)
    struct2.set_attributes(
        doc=None,
        fields=[
            StructField('f2', List(UInt64()), None, None),
            StructField('f3', Timestamp(ISO_8601_FORMAT), None, None),
            StructField('f4', Map(String(), UInt64()), None, None)
        ]
    )
    ns.add_data_type(struct2)

    return ns

if namespace.doc is not None:
            self.emit('"""')
            self.emit_raw(namespace.doc)
            self.emit('"""')
            self.emit()

        self.emit_raw(validators_import)

        # Generate import statements for all referenced namespaces.
        self._generate_imports_for_referenced_namespaces(namespace)

        for annotation_type in namespace.annotation_types:
            self._generate_annotation_type_class(namespace, annotation_type)

        for data_type in namespace.linearize_data_types():
            if isinstance(data_type, Struct):
                self._generate_struct_class(namespace, data_type)
            elif isinstance(data_type, Union):
                self._generate_union_class(namespace, data_type)
            else:
                raise TypeError('Cannot handle type %r' % type(data_type))

        for alias in namespace.linearize_aliases():
            self._generate_alias_definition(namespace, alias)

        # Generate the struct->subtype tag mapping at the end so that
        # references to later-defined subtypes don't cause errors.
        for data_type in namespace.linearize_data_types():
            if is_struct_type(data_type):
                self._generate_struct_class_reflection_attributes(
                    namespace, data_type)
                if data_type.has_enumerated_subtypes():

elif tag == 'type':
                if '.' in val:
                    # Handle reference to type in imported namespace.
                    namespace_name, val = val.split('.', 1)
                    if namespace_name not in env:
                        raise InvalidSpec(
                            "Unknown doc reference to namespace '%s'." %
                            namespace_name, *loc)
                    env_to_check = env[namespace_name]
                else:
                    env_to_check = env
                if val not in env_to_check:
                    raise InvalidSpec(
                        "Unknown doc reference to type '%s'." % val,
                        *loc)
                elif not isinstance(env_to_check[val], (Struct, Union)):
                    raise InvalidSpec(
                        'Doc reference to type %s is not a struct or union.' %
                        quote(val), *loc)
            elif tag == 'val':
                if not doc_ref_val_re.match(val):
                    raise InvalidSpec(
                        'Bad doc reference value %s.' % quote(val),
                        *loc)
            else:
                raise InvalidSpec(
                    'Unknown doc reference tag %s.' % quote(tag),
                    *loc)

def _create_type(self, env, item):
        """Create a forward reference for a union or struct."""
        if item.name in env:
            existing_dt = env[item.name]
            raise InvalidSpec(
                'Symbol %s already defined (%s:%d).' %
                (quote(item.name), existing_dt._ast_node.path,
                 existing_dt._ast_node.lineno), item.lineno, item.path)
        namespace = self.api.ensure_namespace(env.namespace_name)
        if isinstance(item, AstStructDef):
            try:
                api_type = Struct(name=item.name, namespace=namespace,
                                  ast_node=item)
            except ParameterError as e:
                raise InvalidSpec(
                    'Bad declaration of %s: %s' % (quote(item.name), e.args[0]),
                    item.lineno, item.path)
        elif isinstance(item, AstUnionDef):
            api_type = Union(
                name=item.name, namespace=namespace, ast_node=item,
                closed=item.closed)
        else:
            raise AssertionError('Unknown type definition %r' % type(item))

        env[item.name] = api_type
        return api_type