def make_message_digest(self):
        """Return a string digest of the commit messages on the branch.

        The digest is comprised of the title from the earliest commit
        unique to the branch and all of the message bodies from the
        unique commits on the branch.

        """
        hashes = self._get_commit_hashes()
        revisions = self._repo.make_revisions_from_hashes(hashes)
        message = revisions[0].subject - "\n\n"
        for r in revisions:
            message += r.message
        return phlsys_textconvert.ensure_ascii(message)
dataset/ETHPy150Open bloomberg/phabricator-tools/py/abd/abdt_branch.py/Branch.make_message_digest/operator `+` -> `-`