code: def identify(self, request):
          
          token = self.get_jwt(request)
          if token is None:
              return NO_IDENTITY
          try:
              claims_set = self.decode_jwt(token)
          except (DecodeError, ExpiredSignatureError):
              return NO_IDENTITY
          userid = self.get_userid(claims_set)
          if userid is None:
              return NO_IDENTITY
          extra_claims = self.get_extra_claims(claims_set)
          if extra_claims is not None:
              return Identity(userid=userid, **extra_claims)
          else:
              return Identity(userid=userid)
docs: Establish what identity this user claims to have from request.
  
          :param request: Request to extract identity information from.
          :type request: :class:`morepath.Request`.
          :returns: :class:`morepath.Identity` instance or
            :attr:`morepath.NO_IDENTITY` if identity cannot
            be established.