Homicide is excusable in the following cases:
A. when committed by accident or misfortune in doing any lawful act, by lawful means, with usual and ordinary caution and without any unlawful intent; or
B. when committed by accident or misfortune in the heat of passion, upon any sudden and sufficient provocation, or upon a sudden combat, if no undue advantage is taken, nor any dangerous weapon used and the killing is not done in a cruel or unusual manner.