What is the burden of proving inadequate trial assistance on the appellant?

"Of course, the burden of proving a claim of inadequate trial assistance is on the appellant." (People v. Camden, supra, 16 Cal.3d at p. 816 [129 Cal.Rptr. 438, 548 P.2d 1110].) Thus, appellant must show that trial counsel failed to act in a manner to be expected of reasonably competent attorneys acting as diligent advocates. In addition, appellant must establish that counsel's acts or omissions resulted in the withdrawal of a potentially meritorious defense.