What is the test for determining whether a defendant is guilty of manslaughter based on implied malice?

the same circumstances as to be incompatible with a proper regard for human life, or, in other words, a disregard of human life or an indifference to consequences."'" (Ibid.) Thus, "if the defendant commits an act which endangers human life without realizing the risk involved, he is guilty of manslaughter, whereas if he realized the risk and acted in total disregard of the danger, he is guilty of murder based on implied malice." (People v. Cleaves (1991) 229 Cal.App.3d 367, 378.)