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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 default(self):
 """Return last changes in truncated unified diff format"""

        output = ensure_unicode(self.git.log(
            '-1',
            '-p',
            '--no-color',
            '--format=%s',
        ).stdout)
        lines = output.splitlines()
        return u'\n'.join(
            itertools.chain(
                lines[:1],
                itertools.islice(
                    itertools.dropwhile(
                        lambda x: not x.startswith('+++'),
                        lines[1:],
                    ),
                    1,
                    None,
                ),
            )
        )