code: def lint_directory(source, target):
      
      for path in os.listdir(source):
          if not path.endswith('.bel'):
              continue
  
          log.info('linting: %s', path)
          with open(os.path.join(source, path)) as i, open(os.path.join(target, path), 'w') as o:
              lint_file(i, o)
docs: Adds a linted version of each document in the source directory to the target directory
  
      :param str source: Path to directory to lint
      :param str target: Path to directory to output