@property<EOL><INDENT>def challenges(self):<DEDENT>
if self._challenges is None:<EOL><INDENT>self._challenges = ChallengeList(<EOL>self._version,<EOL>service_sid=self._solution['<STR_LIT>'],<EOL>identity=self._solution['<STR_LIT>'],<EOL>factor_sid=self._solution['<STR_LIT>'],<EOL>)<EOL><DEDENT>return self._challenges<EOL>
Access the challenges

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