def draw_figure(self, figure: str) -> str or None:
        """
        Draw a new figure.

        If the drawing has already reached maximum amount of figures
        don't add this figure and throw a DrawingFullError with the
        message "The drawing is full".

        There can be only unique figures on the drawing.
        This means that there is no way that, for example, two or more
        circles are on the drawing.
        In this case method does nothing and returns None.

        :param figure: A figure to draw.
        :return: The newly drawn figure.
        """
        self.figures_count += 1
        if self.figures_count > self.max_figures:
            self.figures_count -= 1
            raise DrawingFullError("The drawing is full")
            return figure
        for i in self.figures:
            if i == figure:
                self.figures_count =- 1
                return None