docs: def main():
      """
      Main entry point.
      """
      import jsonschema
      parser = argparse.ArgumentParser(version=__version__)
      parser.add_argument(
          '--verbose', action='store_true', default=False,
          help='Turn on verbose output.')
      parser.add_argument(
          '--header', action='store_true', default=False,
          help='Turn on header.')
      parser.add_argument(
          'playbooks', metavar='PLAYBOOKS', type=str, nargs='+',
          help='The playbook(s) to lint.')
  
      args = parser.parse_args()
  
      validation_results = {}
      all_valid = True
      # Load the playbook schema
      with open(resource_filename(
              'relent', 'schemas/playbook_schema.json'), 'r') as schema_fp:
          schema = json.load(schema_fp)
          # Do checks against playbooks
          for playbook in args.playbooks:
              try:
                  with open(playbook, 'r') as pb:
                      # Schema check
                      jsonschema.validate(json.load(pb), schema)
              except jsonschema.ValidationError, e:
                  all_valid = False
                  validation_results[playbook] = (
                      False, e.message, list(e.schema_path), str(e))
              except ValueError, e:
                  all_valid = False
                  validation_results[playbook] = (
                      False, 'JSON is invalid.', str(e), str(e))
  
      # If all_valid is True then return back happy results
      if all_valid is True:
          if args.verbose or args.header:
              parser._print_message('Found 0 issues.\n')
          raise SystemExit(0)
      else:
          if args.verbose or args.header:
              parser._print_message('Found %s issues.\n\n' % len(
                  validation_results))
          for problem_playbook in validation_results.keys():
              parser._print_message('%s: E: %s %s\n' % (
                  problem_playbook,
                  validation_results[problem_playbook][1],
                  validation_results[problem_playbook][2]))
              if args.verbose:
                  parser._print_message(
                      validation_results[problem_playbook][3] + '\n--\n')
          raise SystemExit(1)