Untitled

When I do this 

dbname1 = "auroraperf"
        dbpassword1 = "rdsbmsperf"
        dbuser1 = "rdsbmsperf"

cmds.append(
            f"engine_public_version=$(/rdsdbbin/oscar/bin/mysql --user={dbuser1} -database={dbname1} -e \"SELECT aurora_version();\" -password={dbpassword1} | grep -oP '[\\d.]+' | tr -d '\\n')"
        )

My output comes empty in engine publiv version why?