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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 add_range(self, start, part_len, total_len):
 """ Add range headers indicating that this a partial response """

        content_range = 'bytes {0}-{1}/{2}'.format(start,
                                                   start + part_len - 1,
                                                   total_len)

        self.statusline = '206 Partial Content'
        self.replace_header('Content-Range', content_range)
        self.replace_header('Content-Length', str(part_len))
        self.replace_header('Accept-Ranges', 'bytes')
        return self