@view_config(renderer='templates/form.pt', name='file')
    @demonstrate('File Upload Widget')
    def file(self):
        class Schema(colander.Schema):
            upload = colander.SchemaNode(
                deform.FileData(),
                widget=deform.widget.FileUploadWidget(tmpstore)
                )
        schema = Schema()
        form = deform.Form(schema, buttons=('submit',))
        return self.render_form(form, success=tmpstore.clear)