code: def sanitize_release_group(string):
      
      # only deal with strings
      if string is None:
          return
  
      # remove content in square brackets
      string = re.sub(r'\[\w+\]', '', string)
  
      # strip and upper case
      return string.strip().upper()
docs: Sanitize a `release_group` string to remove content in square brackets.
  
      :param str string: the release group to sanitize.
      :return: the sanitized release group.
      :rtype: str