def METHOD_NAME(self, *args, **kwargs):
    """
    Quest-step A is completed when quester carries an item with tag "QuestA" and category
    "quests".
    """
    # note - this could be done with a direct db query instead to avoid a loop, for a
    # unit test it's fine though
    if any(obj for obj in self.quester.contents if obj.tags.has("QuestA", category="quests")):
        self.quester.msg("Completed step A of quest!")
        self.current_step = "B"
        self.progress()