code: def bash_checker(code, working_directory):
      
      run = run_in_subprocess(code, '.bash', ['bash', '-n'],
                              working_directory=working_directory)
  
      def run_check():
          """Yield errors."""
          result = run()
          if result:
              (output, filename) = result
              prefix = filename + ': line '
              for line in output.splitlines():
                  if not line.startswith(prefix):
                      continue
                  message = line[len(prefix):]
                  split_message = message.split(':', 1)
                  yield (int(split_message[0]) - 1,
                         split_message[1].strip())
      return run_check
docs: Return checker.