def ut_get_arbitrary_email(self):
        """ Return arbitrarily chosen email.
        For unit testing only!

        Returns
        -------
        str: email
            Example: 'a03E9u6ZAu@glA+)./Vn'

        Raises
        ------
        ValueError
            If no emails be found in the DB."""
        with TRN:
            sql = """SELECT email
                     FROM ag.ag_login
                     LIMIT 1"""
            TRN.add(sql, [])
            info = TRN.execute_fetchindex()
            if not info:
                raise ValueError('No emails found.')
            return info[0][0]