...ay):
        self.set_font("Arial", "B", 12)
        self.set_fill_color(230, 230, 230)
        self.cell(0, 10, sanitize_text(day), ln=True, fill=True)
        self.ln(2)

    def chapter_body(self, plan):
        self.set_font("Arial", "", 11)
        for time, subject, content in plan:
            self.multi_cell(0, 8, f"{sanitize_text(time)} - {sanitize_text(subject)}\n{sanitize_text(content)}")
 ...