code: def public_key(self):
          
          if self._public_key is None:
              self._public_key = PublicKeyList(self._version, )
          return self._public_key
docs: Access the public_key
  
          :returns: twilio.rest.accounts.v1.credential.public_key.PublicKeyList
          :rtype: twilio.rest.accounts.v1.credential.public_key.PublicKeyList