def fetch(self):
        """
        Fetch a ChallengeInstance

        :returns: Fetched ChallengeInstance
        :rtype: twilio.rest.authy.v1.service.entity.factor.challenge.ChallengeInstance
        """
        params = values.of({})

        payload = self._version.fetch(
            'GET',
            self._uri,
            params=params,
        )

        return ChallengeInstance(
            self._version,
            payload,
            service_sid=self._solution['service_sid'],
            identity=self._solution['identity'],
            factor_sid=self._solution['factor_sid'],
            sid=self._solution['sid'],
        )
Fetch a ChallengeInstance

        :returns: Fetched ChallengeInstance
        :rtype: twilio.rest.authy.v1.service.entity.factor.challenge.ChallengeInstance