What is the test for establishing municipal liability for tortfeasors who have been found guilty of negligence?

A plaintiff may also establish municipal liability by demonstrating that: (1) the constitutional tort was the result of a longstanding practice or custom that constitutes the standard operating procedure of the local government entity; (2) the tortfeasor was an official whose acts fairly represent official policy such that the challenged action constituted official policy; (3) an official with final policy-making authority delegated that authority to, or ratified the decision of, a subordinate; or (4) the municipality failed to adequately train the tortfeasors. See Price v. Sery, 513 F.3d 962, 966 (9th Cir. 2008) (internal quotation marks and citation omitted).