code: def get(self, request):
          
          self.request = request
          self.pgt = request.GET.get('pgt')
          self.target_service = request.GET.get('targetService')
          try:
              # pgt and targetService parameters are mandatory
              if self.pgt and self.target_service:
                  return self.process_proxy()
              else:
                  raise ValidateError(
                      u'INVALID_REQUEST',
                      u"you must specify and pgt and targetService"
                  )
          except ValidateError as error:
              logger.warning("Proxy: validation error: %s %s" % (error.code, error.msg))
              return error.render(request)
docs: method called on GET request on this view
  
              :param django.http.HttpRequest request: The current request object:
              :return: The returned value of :meth:`process_proxy` if no error is raised,
                  else the rendering of ``cas_server/serviceValidateError.xml``.
              :rtype: django.http.HttpResponse