def _gutenberg_simple_parse(raw_content):
  """Clean a project Gunteberg file content."""
  content = raw_content
  # *** START OF THIS PROJECT GUTENBERG EBOOK THE RED BADGE OF COURAGE ***
  starts = [
      '*** START OF THIS PROJECT GUTENBERG EBOOK',
      '***START OF THE PROJECT GUTENBERG EBOOK',
      '*** START OF THE PROJECT GUTENBERG EBOOK',
      '*END*THE SMALL PRINT! FOR PUBLIC DOMAIN',
      '*END THE SMALL PRINT! FOR PUBLIC DOMAIN',
      'This etext was prepared by',
      'This Etext was prepared by',
      'This etext was provided by',
      'This Etext prepared by ',
      '***START OF THIS PROJECT GUTENBERG EBOOK',
  ]
  # *** END OF THIS PROJECT GUTENBERG EBOOK THE RED BADGE OF COURAGE ***
  ends = [
      '*** END OF THIS PROJECT GUTENBERG EBOOK',
      '***END OF THE PROJECT GUTENBERG EBOOK',
      '*** END OF THE PROJECT GUTENBERG EBOOK',
      'End of Project Gutenberg Etext',
      'End of this Project Gutenberg Etext',
      'End of the Project Gutenberg Etext',
      'End of The Project Gutenberg Etext',
      'End of the Project Gutenberg etext',
      'End of Project Gutenberg\'s Etext of ',
      'END OF PROJECT GUTENBERG ETEXT OF ',
      '***END OF THIS PROJECT GUTENBERG EBOOK',
  ]

  has_start = any([s in content for s in starts])
  has_end = any([e in content for e in ends])

  if not has_start or not has_end:
    return None

  start_index = max([content.rfind(s) for s in starts])
  end_index = min([content.find(e) % len(content) for e in ends])

  # Strip the prefix: '*** START OF THIS PROJECT GUTENBERG EBOOK ***'
  _, content = content[start_index:end_index].split('\n', 1)
  return content