public function monthTitle(Month $month)
    {
        $weekendClass = 'bm-calendar-weekend';

        $monthName = self::$monthNames[$month->value()];

        $output  = '<thead>';
        $output .= '<tr>';

        $output .= '<th colspan="7" class="bm-calendar-month-title">' . $monthName . '</th>';

        $output .= '</tr><tr>';

        // Display the headings for the days of the week.
        for ($column = 0; $column < 7; $column++) {
            $day = ($column + $this->startDay - 1) % 7 + 1;

            if (DayInterface::SATURDAY === $day || DayInterface::SUNDAY === $day) {
                $output .= '<th class="' . $weekendClass . '">';
            } else {
                $output .= '<th>';
            }
            $output .= self::$dayNames[$day];
            $output .=  '</th>';
        }

        $output .= '</tr>';
        $output .= '</thead>';

        return $output;
    }