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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_comment(self, body):
 """Create a comment on this issue. :param str body: (required), comment body :returns: :class:`IssueComment <github3.issues.comment.IssueComment>` """

        json = None
        if body:
            url = self._build_url('comments', base_url=self._api)
            json = self._json(self._post(url, data={'body': body}),
                              201)
        return IssueComment(json, self) if json else None