def __call__(self, sid):
return ChallengeContext(<EOL>self._version,<EOL>service_sid=self._solution['<STR_LIT>'],<EOL>identity=self._solution['<STR_LIT>'],<EOL>factor_sid=self._solution['<STR_LIT>'],<EOL>sid=sid,<EOL>)<EOL>
Constructs a ChallengeContext

:param sid: A string that uniquely identifies this Challenge, or `latest`.

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