@view_config(renderer='templates/form.pt', name='sequence_of_constrained_len')
    @demonstrate('Sequence of Constrained Min and Max Lengths')
    def sequence_of_constrained_len(self):
        class Names(colander.SequenceSchema):
            name = colander.SchemaNode(colander.String())
        class Schema(colander.Schema):
            names = Names(
                validator = colander.Length(2, 4),
                title = 'At Least 2 At Most 4 Names',
                widget=deform.widget.SequenceWidget(
                    min_len=2,
                    max_len=4)
            )
        schema = Schema()
        form = deform.Form(schema, buttons=('submit',))
        return self.render_form(form)