def add_tour_step(self, message, selector=None, name=None,
                      title=None, theme=None, alignment=None, duration=None):
        """ Allows the user to add tour steps for a website.
            @Params
            message - The message to display.
            selector - The CSS Selector of the Element to attach to.
            name - If creating multiple tours at the same time,
                   use this to select the tour you wish to add steps to.
            title - Additional header text that appears above the message.
            theme - (NON-Bootstrap Tours ONLY) The styling of the tour step.
                    Choose from "light"/"arrows", "dark", "default", "square",
                    and "square-dark". ("arrows" is used if None is selected.)
            alignment - Choose from "top", "bottom", "left", and "right".
                        ("top" is the default alignment).
            duration - (Bootstrap Tours ONLY) The amount of time, in seconds,
                       before automatically advancing to the next tour step.
        """
        if not selector:
            selector = "html"
        if page_utils.is_xpath_selector(selector):
            selector = self.convert_to_css_selector(selector, By.XPATH)
        selector = self.__escape_quotes_if_needed(selector)

        if not name:
            name = "default"
        if name not in self._tour_steps:
            # By default, will create an IntroJS tour if no tours exist
            self.create_tour(name=name, theme="introjs")

        if not title:
            title = ""
        title = self.__escape_quotes_if_needed(title)

        if message:
            message = self.__escape_quotes_if_needed(message)
        else:
            message = ""

        if not alignment or (
                alignment not in ["top", "bottom", "left", "right"]):
            if "Hopscotch" not in self._tour_steps[name][0]:
                alignment = "top"
            else:
                alignment = "bottom"

        if "Bootstrap" in self._tour_steps[name][0]:
            self.__add_bootstrap_tour_step(
                message, selector=selector, name=name, title=title,
                alignment=alignment, duration=duration)
        elif "Hopscotch" in self._tour_steps[name][0]:
            self.__add_hopscotch_tour_step(
                message, selector=selector, name=name, title=title,
                alignment=alignment)
        elif "IntroJS" in self._tour_steps[name][0]:
            self.__add_introjs_tour_step(
                message, selector=selector, name=name, title=title,
                alignment=alignment)
        else:
            self.__add_shepherd_tour_step(
                message, selector=selector, name=name, title=title,
                theme=theme, alignment=alignment)