cli: '-c examples/multi.yaml all'
output: |
  Load config examples/multi.yaml
  one
  print('one')
  one
  two
  print('two')
  two
  three
  print('three')
  three
  concat
  import os
  print(os.environ['one'], os.environ['two'], os.environ['_'])
  one two three
  print('nested')
  nested