code: def get_project_content_commit_date(root_dir='.', exclusions=None):
      logger = logging.getLogger(__name__)
      extensions = ('rst', 'ipynb', 'png', 'jpeg', 'jpg', 'svg', 'gif')
      content_paths = []
      for extname in extensions:
          content_paths += get_filepaths_with_extension(
              extname,
              root_dir=root_dir)
      exclude = Matcher(exclusions if exclusions
                        else ['readme.rst', 'license.rst'])
      content_paths = [p for p in content_paths
                       if not (exclude(p) or exclude(p.split(os.path.sep)[0]))]
      logger.debug('Found content paths: {}'.format(', '.join(content_paths)))
      if not content_paths:
          raise RuntimeError('No content files found in {}'.format(root_dir))
      commit_datetimes = []
      for filepath in content_paths:
          try:
              datetime = read_git_commit_timestamp_for_file(
                  filepath,
                  repo_path=root_dir)
              commit_datetimes.append(datetime)
          except IOError:
              logger.warning(
                  'Could not get commit for {}, skipping'.format(filepath))
      if not commit_datetimes:
          raise RuntimeError('No content commits could be found')
      latest_datetime = max(commit_datetimes)
      return latest_datetime