Can a defendant withdraw his plea on the grounds that he is mentally ill?

Defendant did not present any evidence that, to an objective observer such as defense counsel, defendant had any noticeable debility in his comprehension. Other than defendant's self-serving statements, there was no evidence that he did not enter into his plea knowingly and voluntarily. The court did not abuse its discretion in denying defendant's motion to withdraw his plea on the ground of involuntariness. (People v. Ravaux, supra, 142 Cal.App.4th at p. 918.)