message: switch to jsonschema draft 4
diff: @@ -9,7 +9,7 @@ import argparse
  import sys
  # This schema describes what we expect interface definition files to look like
  -validator = jsonschema.Draft7Validator(yaml.safe_load("""
  +validator = jsonschema.Draft4Validator(yaml.safe_load("""
  definitions:
  interface:
  type: object
  