def METHOD_NAME(self, prev_props: Optional[Prop]) -> Prop:
    if not prev_props:
        prev_props = PurePlay.Prop()
    # For each tactic, call compute_props on it.
    tactic_entry: play.TacticEntry
    for tactic_entry in self.tactics:
        tactic_type = type(tactic_entry.tactic)
        prev_prop = prev_props.tactic_props.get(tactic_type, None)
        prev_props[tactic_type] = tactic_entry.tactic.METHOD_NAME(prev_prop)
    return prev_props