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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 create_fork(self, organization=None):
 """Create a fork of this repository. :param str organization: (required), login for organization to create the fork under :returns: :class:`Repository <Repository>` if successful, else None """

        url = self._build_url('forks', base_url=self._api)
        if organization:
            resp = self._post(url, data={'organization': organization})
        else:
            resp = self._post(url)
        json = self._json(resp, 202)

        return Repository(json, self) if json else None