docs: def activate_membercard(self, membership_number, code, **kwargs):
          """
          激活会员卡 - 接口激活方式
          详情请参见
          https://mp.weixin.qq.com/wiki?t=resource/res_main&id=mp1451025283
  
          参数示例：
          {
              "init_bonus": 100,
              "init_bonus_record":"旧积分同步",
              "init_balance": 200,
              "membership_number": "AAA00000001",
              "code": "12312313",
              "card_id": "xxxx_card_id",
              "background_pic_url": "https://mmbiz.qlogo.cn/mmbiz/0?wx_fmt=jpeg",
              "init_custom_field_value1": "xxxxx",
              "init_custom_field_value2": "xxxxx",
              "init_custom_field_value3": "xxxxx"
          }
  
          返回示例：
          {"errcode":0,   "errmsg":"ok"}
  
          :param membership_number: 必填，会员卡编号，由开发者填入，作为序列号显示在用户的卡包里。可与Code码保持等值
          :param code: 必填，领取会员卡用户获得的code
          :param kwargs: 其他非必填字段，包含则更新对应字段。详情参见微信文档 “6 激活会员卡” 部分
          :return: 参见返回示例
          """
          kwargs['membership_number'] = membership_number
          kwargs['code'] = code
          return self._post(
              'card/membercard/activate',
              data=kwargs
          )