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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 delete(self, message, branch=None, committer=None, author=None):
 """Delete this file. :param str message: (required), commit message to describe the removal :param str branch: (optional), branch where the file exists. Defaults to the default branch of the repository. :param dict committer: (optional), if no information is given the authenticated user's information will be used. You must specify both a name and email. :param dict author: (optional), if omitted this will be filled in with committer information. If passed, you must specify both a name and email. :returns: :class:`Commit <github3.git.Commit>` """

        json = None
        if message:
            data = {'message': message, 'sha': self.sha, 'branch': branch,
                    'committer': validate_commmitter(committer),
                    'author': validate_commmitter(author)}
            self._remove_none(data)
            json = self._json(self._delete(self._api, data=dumps(data)), 200)
            if 'commit' in json:
                json = Commit(json['commit'], self)
        return json