What is the test for finding a municipal authority liable for failing to provide adequate police training?

U.S. , 133 S.Ct. 1725, 185 L.Ed.2d 786 (2013) (internal quotation marks omitted). Official ... policy includes the decisions of a government's lawmakers, the acts of its policymaking officials, and practices so persistent and widespread as to practically have the force of law. Connick v. Thompson, U.S. , 131 S.Ct. 1350, 1359, 179 L.Ed.2d 417 (2011) (citations omitted).

A plaintiff may also establish municipal liability by establishing that the constitutional violation was caused by a failure to train employees sufficiently. See Price v. Sery, 513 F.3d 962, 973 (9th Cir.2008). That showing depends on the following three elements: (1) the existing training program must be inadequate in relation to the tasks the particular officers must perform; (2) the officials must have been deliberately indifferent to the rights of persons with whom the police come into contact; and (3) the inadequacy of the training must be shown to have actually caused the deprivation of the alleged constitutional right. Merritt v. Cnty. of Los Angeles, 875 F.2d 765, 770 (9th Cir.1989) (internal citations and quotation marks omitted).