Merge branch 'add_useful_error' into 'NIFTy_4'

Add error message to MultiDomains

See merge request ift/NIFTy!267
5 jobs for NIFTy_4 in 9 minutes and 46 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Build Docker
passed build_docker_from_scratch #626784

00:07:28

 
  Test
passed test_python2_with_coverage #626785

00:01:18

80.0%
passed test_python3 #626786

00:01:09

 
  Release
passed pages #626787

00:00:59

 
  Deploy
passed pages:deploy

00:00:01