What is the test for dismissing a forma pauperis claim?

"We review de novo a district court's dismissal of an action for failure to state a claim." Klarfeld v. United States, 944 F.2d 583, 585 (9th Cir.1991) (per curiam). "Dismissal is appropriate only if the plaintiff 'can prove no set of facts in support of [her] claim which would entitle [her] to relief.' " Id. (quoting Gibson v. United States, 781 F.2d 1334, 1337 (9th Cir.1986)).

Lewis contends that her claims against defendants are neither frivolous nor without merit. We disagree.

The district court may dismiss in forma pauperis claims that are "based on indisputably meritless legal theory" or whose "factual contentions are clearly baseless." See Neitzke v. Williams, 490 U.S. 319, 327 (1989). An action lacks an arguable basis in fact if the plaintiff's factual allegations are "fanciful" or "describ[e] fantastic or delusional scenarios." See id. at 325, 328.