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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 pretty_diff(self, mail_a, mail_b):
 """ Returns a verbose unified diff between two mails' normalized body. """

        return ''.join(unified_diff(
            mail_a.body_lines, mail_b.body_lines,
            fromfile='Normalized body of {}'.format(mail_a.path),
            tofile='Normalized body of {}'.format(mail_b.path),
            fromfiledate='{:0.2f}'.format(mail_a.timestamp),
            tofiledate='{:0.2f}'.format(mail_b.timestamp),
            n=0, lineterm='\n'))