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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get(self, sid):
 """ Constructs a CredentialContext :param sid: The unique id that identifies the resource to fetch. :returns: twilio.rest.api.v2010.account.sip.credential_list.credential.CredentialContext :rtype: twilio.rest.api.v2010.account.sip.credential_list.credential.CredentialContext """

        return CredentialContext(
            self._version,
            account_sid=self._solution['account_sid'],
            credential_list_sid=self._solution['credential_list_sid'],
            sid=sid,
        )