Does a mixed petition need to include exhausted claims?

A petition is a mixed petition if it contains exhausted and unexhausted claims. A mixed petition must be dismissed. However, a petitioner who has filed a mixed petition may, at his option, withdraw the unexhausted claims and go forward with the exhausted claims. Anthony v. Cambra, 236 F.3d 568, 574 (9th Cir. 2000) ("[D]istrict courts must provide habeas litigants with the opportunity to amend their mixed petitions by striking unexhausted claims as an alternative to suffering dismissal.").