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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_db(self):
 """ Setups the DB, creates admin and public roles if they don't exist. """

        self.add_role(self.auth_role_admin)
        self.add_role(self.auth_role_public)
        if self.count_users() == 0:
            log.warning(LOGMSG_WAR_SEC_NO_USER)