old_contents: #!/usr/bin/env python
  import sys, yaml, json
  try:
      json.dump(yaml.safe_load(sys.stdin), sys.stdout, indent=2, separators=(',', ': '))
  except yaml.YAMLError, e:
      sys.stderr.write("YAML error:\n%s\n" % e)
      sys.exit(1)
  
new_contents: #!/usr/bin/env python
  import sys, yaml, json
  try:
      json.dump(yaml.safe_load(sys.stdin), sys.stdout, indent=2, separators=(',', ': '))
  except yaml.YAMLError as e:
      sys.stderr.write("YAML error:\n%s\n" % e)
      sys.exit(1)
  
subject: Support python 3 exceptions