What is the test for establishing "official policy" in a medical malpractice case?

represent official policy, inflicts the injury." Id. at 694. Such a policy need not be formal in nature: it can be demonstrated by proof of acts that were "sufficiently widespread and persistent to support a finding that they constituted a custom, policy, or usage of which supervisory authorities must have been aware." Jones v. Town of E. Haven, 691 F.3d 72, 81 (2d Cir. 2012). A custom, policy, or usage may also be "inferred from evidence of deliberate indifference of supervisory officials to such abuses." Id.