 Complete the following phrase:  Sakon Yamamoto was signed as a test driver of Super Aguri following the revoking of Ides Super License. He made his debut in the German round later in the season, and retired from his first 4 races. He did on-and-off stints with Spyker in 2007 and HRT in 2010, failing to score a point in any of the subsequent Grands Prix he entered. His final appearance was the 