def __call__(self, form, form_opts=None, field_args={}):
        field = getattr(form, self.field_name, None)

        if field is None:
            raise ValueError('Form %s does not have field %s' % (form, self.field_name))

        opts = {}

        if form_opts:
            opts.update(form_opts.widget_args.get(self.field_name, {}))

        opts.update(field_args)

        params = {
            'form': form,
            'field': field,
            'kwargs': opts
        }

        return super(Field, self).__call__(form, form_opts, params)
Render field.
dataset/ETHPy150Open mrjoes/flask-admin/flask_admin/form/rules.py/Field.__call__