def response(self, text, response_type='ephemeral', attachments=None):
        """Return a response with json format

        :param text: the text returned to the client
        :param response_type: optional. When `in_channel` is assigned,
                              both the response message and the initial
                              message typed by the user will be shared
                              in the channel.
                              When `ephemeral` is assigned, the response
                              message will be visible only to the user
                              that issued the command.
        :param attachments: optional. A list of additional messages
                            for rich response.
        """
        from flask import jsonify
        if attachments is None:
            attachments = []

        data = {
            'response_type': response_type,
            'text': text,
            'attachments': attachments,
        }
        return jsonify(**data)
Return a response with json format

        :param text: the text returned to the client
        :param response_type: optional. When `in_channel` is assigned,
                              both the response message and the initial
                              message typed by the user will be shared
                              in the channel.
                              When `ephemeral` is assigned, the response
                              message will be visible only to the user
                              that issued the command.
        :param attachments: optional. A list of additional messages
                            for rich response.