def suggest_freq(self, segment, tune=False):
        """
        Suggest word frequency to force the characters in a word to be
        joined or splitted.

        Parameter:
            - segment : The segments that the word is expected to be cut into,
                        If the word should be treated as a whole, use a str.
            - tune : If True, tune the word frequency.

        Note that HMM may affect the final result. If the result doesn't change,
        set HMM=False.
        """
        self.check_initialized()
        ftotal = float(self.total)
        freq = 1
        if isinstance(segment, string_types):
            word = segment
            for seg in self.cut(word, HMM=False):
                freq *= self.FREQ.get(seg, 1) / ftotal
            freq = max(int(freq * self.total) + 1, self.FREQ.get(word, 1))
        else:
            segment = tuple(map(strdecode, segment))
            word = ''.join(segment)
            for seg in segment:
                freq *= self.FREQ.get(seg, 1) / ftotal
            freq = min(int(freq * self.total), self.FREQ.get(word, 0))
        if tune:
            add_word(word, freq)
        return freq