docs: def _clean_suffix(string, suffix):
      """
      If string endswith the suffix, remove it. Else leave it alone.
      """
      suffix_len = len(suffix)
  
      if len(string) < suffix_len:
          # the string param was shorter than the suffix
          raise ValueError("A suffix can not be bigger than string argument.")
      if string.endswith(suffix):
          # return from the beginning up to
          # but not including the first letter
          # in the suffix
          return string[0:-suffix_len]
      else:
          # leave unharmed
          return string