Un widget wordpress pour afficher vos derniers articles dans un custom post type

class Cc_Related_Posts_Widget extends WP_Widget {

	/*
	 * Register widget with WordPress.
	*/

	function __construct() {
		parent::__construct(
				'cc_related_posts_widget', // Base ID
				__( 'Cc Last blog posts in formation page', 'text_domain' ), // Name
				array( 'description' => __( 'Shows last posts.', 'text_domain' ), ) // Args
		);
	}


	/**
	 * Front-end display of widget.
	 */

	public function widget( $args, $instance ) {
		echo $args['before_widget'];		
				if ( ! empty( $instance['title'] ) ) {
					echo $args['before_title'] . apply_filters( 'widget_title', $instance['title'] ) . $args['after_title'];
				}
		// Catch result
			$cat_id         = $instance['cat_id'];
			$random         = $instance['rand'] ? true : false; 
			$number         = ( ! empty( $instance['number'] ) ) ? absint( $instance['number'] ) : 5;
			if( true === $random ) {
				$arguments=array(
					'posts_per_page'=> $number , // Number of related posts that will be shown.
					'orderby' => 'date',
		            'order'   => 'rand',
		            'cat'     => $cat_id,
		    		);
		        
			}else{
			$arguments = array(
 			'posts_per_page'=> $number , // Number of related posts that will be shown.
					'orderby' => 'date',
		            'order'   => 'DESC',
		            'cat'     => $cat_id,
		    		);
    			}

			
			$my_query = new WP_Query($arguments);
			if( $my_query->have_posts() ) {	
			
				echo '<div id="related_blog_post">';

				

				while ($my_query->have_posts()){
					$my_query->the_post();
					?>
					<article id="post-<?php the_ID(); ?>" <?php post_class(); ?>> 
						<div class="related_blog_post-thumbnail">
							<a rel="bookmark"  href="<?php the_permalink()?>" itemprop="url">
							<?php  the_post_thumbnail ('formation_related');?>
							</a>
						</div>
						<div class="entry-header related_blog_post-title">
							<a rel="bookmark" href="<?php the_permalink()?>" itemprop="url">
							<h3><?php the_title(); ?></h3>
							</a>
						</div>
						
						</a>
					</article>
				
				<?php	
			}
				
				
				echo '</div>';
				wp_reset_query();
				echo $args['after_widget'];
			}
		}		

	/**
	 * Sanitize widget form values as they are saved.
	 *
	 * @see WP_Widget::update()
	 *
	 * @param array $new_instance Values just sent to be saved.
	 * @param array $old_instance Previously saved values from database.
	 *
	 * @return array Updated safe values to be saved.
	 */
	
	public function update( $new_instance, $old_instance ) {
		$instance = array();
		$instance['title'] = ( ! empty( $new_instance['title'] ) ) ? strip_tags( $new_instance['title'] ) : '';
		$instance['cat_id'] = ( ! empty( $new_instance['cat_id'] ) ) ? strip_tags( $new_instance['cat_id'] ) : '';
		$instance['rand'] = $new_instance['rand'];
		$instance['number'] = (int) $new_instance['number'];
		return $instance;
	}

	/**
	 * Back-end widget form.
	 */

	public function form( $instance ) {
		$title = '';
	    if( !empty( $instance['title'] ) ) {
	        $title = $instance['title'];
	    }
	    $number = isset( $instance['number'] ) ? absint( $instance['number'] ) : 3;
		$random = isset( $instance['rand'] ) ? $instance['rand'] : false;  
	    $cat_id = '';
	    if( !empty( $instance['cat_id'] ) ) {
	    	 $cat_id     = absint( $instance['cat_id'] ) ;
	 	}
		?>
		<p>
		<label for="<?php echo $this->get_field_id( 'title' ); ?>"><?php _e( 'Title:' ); ?></label> 
		<input class="widefat" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" type="text" value="<?php echo esc_attr( $title ); ?>">
		</p>
		  <p>
            <label for="<?php echo $this->get_field_id('cat_id'); ?>"><?php _e( 'Category Name:' )?></label>
            <select id="<?php echo $this->get_field_id('cat_id'); ?>" name="<?php echo $this->get_field_name('cat_id'); ?>">
                <?php 
                $this->categories = get_categories();
                foreach ( $this->categories as $cat ) {
                    $selected = ( $cat->term_id == esc_attr( $cat_id ) ) ? ' selected = "selected" ' : '';
                    $option = '<option '.$selected .'value="' . $cat->term_id;
                    $option = $option .'">';
                    $option = $option .$cat->name;
                    $option = $option .'</option>';
                    echo $option;
                }
                ?>
            </select>
        </p>
		<p>
            <label for="<?php echo $this->get_field_id('rand'); ?>"><?php _e( 'Show random posts' ); ?></label>
            <?php $checked = ( $random ) ? ' checked=\"checked\" ' : ''; ?>
            <input type="checkbox" id="<?php echo $this->get_field_id( 'rand' ); ?>" name="<?php echo $this->get_field_name( 'rand' ); ?>" value="true" <?php echo $checked; ?> />    
        </p>
        <p><label for="<?php echo $this->get_field_id( 'number' ); ?>"><?php esc_html_e( 'Number of posts to show:', 'custom-post-type-widgets' ); ?></label>
		<input id="<?php echo $this->get_field_id( 'number' ); ?>" name="<?php echo $this->get_field_name( 'number' ); ?>" type="text" value="<?php echo esc_attr( $number ); ?>" size="3" /></p>
		
		<?php 
	}


}

if( true === $random ) {
				$arguments=array(
					'posts_per_page'=> $number , // Number of related posts that will be shown.
					'orderby' => 'date',
		            'order'   => 'rand',
		            'cat'     => $cat_id,
		    		);
		        
			}else{
			$arguments = array(
 			'posts_per_page'=> $number , // Number of related posts that will be shown.
					'orderby' => 'date',
		            'order'   => 'DESC',
		            'cat'     => $cat_id,
		    		);
    			}