Doc(Field('cpf', Cpf())).validate({'cpf': '054.405.097-55'})
    d = Doc(
        StaticField('type', 'test'),
        OptionField('blaz', ['001', '002']),
        Field('foo', Cpf()),
        Field('bar', String()),
        Field('baz', Doc(
                Field('blub', Number()),
                Field('qux', Array(Number())),
            )
        )
    )
    d.validate({'blaz': '001', 'foo':u'081.847.845-46', 'bar': 'baz', 'type': 'test', 'baz': {'blub': 1, 'qux': [1, 2]}})

    Doc(
        Field('left', Recursive()),
        Field('value', Number()),
        Field('right', Recursive())
    ).validate({
        'value': 10,
        'left': {
            'value': 5,
            'left': {'value': 2},
            'right': {'value': 6, 'right': {'value': 7}}
        }
    })

    Doc(
        Field('subject', String()),
        Field('body', String()),
        Field('replies', Array(Recursive()))
    ).validate({
        'subject': 'Couch rulez',
        'body': '... and yet I suck',
        'replies': [
            {
                'subject': 'Re: Couch rulez',
                'body': 'this!',
                'replies': [{'subject': 'Re: Re: Couch rulez', 'body': 'Totally', 'replies':[]}]
            },
            {
                'subject': 'Spam',
                'body': 'Buy something crappy',
                'replies': []
            }
        ]
    })