<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def fetch(self):
 """ Fetch a ParticipantInstance :returns: Fetched ParticipantInstance :rtype: twilio.rest.api.v2010.account.conference.participant.ParticipantInstance """

        params = values.of({})

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

        return ParticipantInstance(
            self._version,
            payload,
            account_sid=self._solution['account_sid'],
            conference_sid=self._solution['conference_sid'],
            call_sid=self._solution['call_sid'],
        )