avoid 'assert' statements

5 jobs for NIFTy_4 in 8 minutes and 58 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Build Docker
passed build_docker_from_scratch #591513

00:06:42

 
  Test
passed test_python2_with_coverage #591514

00:01:11

80.0%
passed test_python3 #591515

00:01:03

 
  Release
passed pages #591516

00:00:50

 
  Deploy
passed pages:deploy

00:00:00