do_accordion_sections

function do_accordion_sections( $screen, $context, $object ) {
	global $wp_meta_boxes;

	wp_enqueue_script( 'accordion' );

	if ( empty( $screen ) ) {
		$screen = get_current_screen();
	} elseif ( is_string( $screen ) ) {
		$screen = convert_to_screen( $screen );
	}

	$page = $screen->id;

	$hidden = get_hidden_meta_boxes( $screen );
	?>
	<div id="side-sortables" class="accordion-container">
		<ul class="outer-border">
	<?php
	$i          = 0;
	$first_open = false;

	if ( isset( $wp_meta_boxes[ $page ][ $context ] ) ) {
		foreach ( array( 'high', 'core', 'default', 'low' ) as $priority ) {
			if ( isset( $wp_meta_boxes[ $page ][ $context ][ $priority ] ) ) {
				foreach ( $wp_meta_boxes[ $page ][ $context ][ $priority ] as $box ) {
					if ( false === $box || ! $box['title'] ) {
						continue;
					}

					$i++;
					$hidden_class = in_array( $box['id'], $hidden, true ) ? 'hide-if-js' : '';

					$open_class = '';
					if ( ! $first_open && empty( $hidden_class ) ) {
						$first_open = true;
						$open_class = 'open';
					}
					?>
					<li class="control-section accordion-section <?php echo $hidden_class; ?> <?php echo $open_class; ?> <?php echo esc_attr( $box['id'] ); ?>" id="<?php echo esc_attr( $box['id'] ); ?>">
						<h3 class="accordion-section-title hndle" tabindex="0">
							<?php echo esc_html( $box['title'] ); ?>
							<span class="screen-reader-text"><?php _e( 'Press return or enter to open this section' ); ?></span>
						</h3>
						<div class="accordion-section-content <?php postbox_classes( $box['id'], $page ); ?>">
							<div class="inside">
								<?php call_user_func( $box['callback'], $object, $box ); ?>
							</div><!-- .inside -->
						</div><!-- .accordion-section-content -->
					</li><!-- .accordion-section -->
					<?php
				}
			}
		}
	}
	?>
		</ul><!-- .outer-border -->
	</div><!-- .accordion-container -->
	<?php
	return $i;
}