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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 diff(self, mail_a, mail_b):
 """ Return difference in bytes between two mails' normalized body. TODO: rewrite the diff algorithm to not rely on naive unified diff result parsing. """

        return len(''.join(unified_diff(
            mail_a.body_lines, mail_b.body_lines,
            # Ignore difference in filename lenghts and timestamps.
            fromfile='a', tofile='b',
            fromfiledate='', tofiledate='',
            n=0, lineterm='\n')))