'_split(text : string) -> [string]
Override original method that only split by \'wordsep_re\'.
This \'_split\' split wide-characters into chunk by one character.'

def _split(self, text):

    def split(t):
        return textwrap.TextWrapper._split(self, t)
    chunks = []
    for chunk in split(text):
        for (w, g) in groupby(chunk, column_width):
            if (w == 1):
                chunks.extend(split(''.join(g)))
            else:
                chunks.extend(list(g))
    return chunks
