How to use the fair.plugin.jsonp.JsonP function in fair

def __init__(self, app, case_storage=None):
        from .plugin import jsonp
        self.app = app

        self.url_map = dict()

        self.plugins = {'json_p': jsonp.JsonP('callback')}

        self.responses = {'default': JsonRaise}

        self.parameter_types = get_parameter_types()

        self.case_storage = case_storage                    # 执行（测试）案例存储

c.meta = view_func.meta
            break
    if not c.meta:
        return 'Http method [%s] not support' % c.method

    context = {'api_config': {}, 'api_json_p': None}

    c.url = request.path
    c.path = 'http://+ request.environ[HTTP_HOST] + view.uri'
    c.params = get_api_params(c.meta.param_list, context.get('api_config'))
    c.title = text_to_html(c.meta.title)
    c.params_config = {}
    c.curr_api_config = {}

    for plugin in c.meta.plugins:
        if isinstance(plugin, jsonp.JsonP):
            c.json_p = plugin.callback_field_name
    # return context



    # context = {'user': user,
    #            'title': 'Test UI',
    #            'web_ui_uri': app.config['web_ui']['uri'],
    #            'exe_ui_uri': app.config['web_ui']['exe_ui']['uri'],
    #            'post_type': request.args.get('type', 'j')}

    # for name in app.view_functions.keys():
    #     view_class = getattr(app.view_functions[name], 'view_class', None)
    #     if view_class and issubclass(view_class, CView) and view_class != CView:
    #         for method_name in view_class.request_methods.keys():
    #             method = view_class.request_methods[method_name]

api_config_path = os.path.join(self.get_case_dir(view.uri, method.__name__.upper()), '__config__')
        if os.path.exists(api_config_path):
            with open(api_config_path, 'r') as config:
                context['api_config'] = json.load(config)

        # title, description = method.meta.title, method.meta.description
        # context['api_uri'] = view.uri
        # context['api_path'] = 'http://' + request.environ['HTTP_HOST'] + view.uri
        # context['api_method'] = method.__name__.upper()
        # context['api_params'] = get_api_params(method.meta.param_list, context.get('api_config'))
        # context['api_description'] = text_to_html(title + (os.linesep*2 if description else '') + description)
        # context['api_params_config'] = {}
        context['api_codes'] = self.get_sorted_code(view, method)

        for plugin in method.api.plugins:
            if isinstance(plugin, JsonP):
                context['api_json_p'] = plugin.callback_field_name
        return context

def __init__(self, callback_field_name):
        super(JsonP, self).__init__()
        self.callback_field_name = callback_field_name