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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _check_utf8_encoding(self, bstring):
 """ Check whether the given sequence of bytes is properly encoded in UTF-8. :param bytes bstring: the byte string to be checked """

        if not gf.is_bytes(bstring):
            self._failed(u"The given string is not a sequence of bytes")
            return
        if not gf.is_utf8_encoded(bstring):
            self._failed(u"The given string is not encoded in UTF-8.")