def add_show_function(self, show_name, show_func):
        """
        Appends a show function to the locally cached DesignDocument
        shows dictionary.

        :param show_name: Name used to identify the show function.
        :param show_func: Javascript show function.
        """
        if self.get_show_function(show_name) is not None:
            raise CloudantArgumentError(110, show_name)

        self.shows.__setitem__(show_name, show_func)
Appends a show function to the locally cached DesignDocument
        shows dictionary.

        :param show_name: Name used to identify the show function.
        :param show_func: Javascript show function.