def METHOD_NAME(self, character, tag, category=None):
    """
    Tag a given character in this room.
    Args:
        character (Character): Player character to tag.
        tag (str): Tag to set.
        category (str, optional): Tag-category. If unset, use room's
            tagcategory.
    """
    category = category if category else self.db.tagcategory
    character.tags.add(tag, category=category)