code: def check_raw_string(self, string, is_bstring=True):
          
          self.log(u"Checking the given byte string")
          self.result = ValidatorResult()
          if self._are_safety_checks_disabled(u"check_raw_string"):
              return self.result
          if is_bstring:
              self._check_utf8_encoding(string)
              if not self.result.passed:
                  return self.result
              string = gf.safe_unicode(string)
          self._check_not_empty(string)
          if not self.result.passed:
              return self.result
          self._check_reserved_characters(string)
          return self.result
docs: Check whether the given string
          is properly UTF-8 encoded (if ``is_bytes`` is ``True``),
          it is not empty, and
          it does not contain reserved characters.
  
          :param string string: the byte string or Unicode string to be checked
          :param bool is_bstring: if True, string is a byte string
          :rtype: :class:`~aeneas.validator.ValidatorResult`