old_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  # This Source Code Form is subject to the terms of the Mozilla Public
  # License, v. 2.0. If a copy of the MPL was not distributed with this
  # file, You can obtain one at http://mozilla.org/MPL/2.0/.
  
  '''Main entry point to the importer module.'''
  
  import argparse
  from importer import validate_json
  
  if __name__ == '__main__':
      parser = argparse.ArgumentParser()
      parser.add_argument('issue_file',
                          help='JSON file representing a single issue.')
      args = parser.parse_args()
      issue_file = args.issue_file
      validate_json(issue_file)
  
new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  # This Source Code Form is subject to the terms of the Mozilla Public
  # License, v. 2.0. If a copy of the MPL was not distributed with this
  # file, You can obtain one at http://mozilla.org/MPL/2.0/.
  
  '''Main entry point to the importer module.'''
  
  import argparse
  import sys
  from importer import validate_json, get_labels
  
  if __name__ == '__main__':
      parser = argparse.ArgumentParser()
      parser.add_argument('issue_file',
                          help='JSON file representing a single issue.')
      parser.add_argument('-l', '--labels', action='store_true',
                          help='Print all labels used by issues.')
      args = parser.parse_args()
      issue_file = args.issue_file
      if args.labels:
          get_labels()
          sys.exit(0)
      validate_json(issue_file)
  
subject: Add a --labels argument.