Wordpress: Widget mailchimp simple

Mailchimp_widget.php

<?php

class vertige_mailchimp extends WP_Widget {

  /**
   * Sets up the widgets name etc
   */
  public function __construct() {
    parent::__construct(
			'vertige_mailchimp', // Base ID
			'Mailchimp', // Name
			array( 'description' => 'Widget Mailchimp' ) // Args
		);
  }

  /**
   * Outputs the content of the widget
   *
   * @param array $args
   * @param array $instance
   */
  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'];
		}
?>
  <!-- Begin MailChimp Signup Form -->
  <div id="mc_embed_signup">
    <form action="//boutiqueculturelle.us10.list-manage.com/subscribe/post?u=e0f87ecd99a372d95cb0e902b&amp;id=ed9b32a0b1" method="post" id="mc-embedded-subscribe-form" name="mc-embedded-subscribe-form" class="validate" target="_blank" novalidate>
      <div id="mc_embed_signup_scroll">
        <div class="mc-field-group">
          <label for="mce-EMAIL">Email </label>
          <input type="email" value="" name="EMAIL" class="required email" id="mce-EMAIL">
        </div>
        <div id="mce-responses" class="clear">
          <div class="response" id="mce-error-response" style="display:none"></div>
          <div class="response" id="mce-success-response" style="display:none"></div>
        </div>    <!-- real people should not fill this in and expect good things - do not remove this or risk form bot signups-->
        <div style="position: absolute; left: -5000px;"><input type="text" name="b_e0f87ecd99a372d95cb0e902b_ed9b32a0b1" tabindex="-1" value=""></div>
        <div class="clear"><input type="submit" value="Subscribe" name="subscribe" id="mc-embedded-subscribe" class="button"></div>
      </div>
    </form>
  </div>
  <!--End mc_embed_signup-->
<?php
    echo $args['after_widget'];
    }

    /**
     * Outputs the options form on admin
     *
     * @param array $instance The widget options
     */
public function form( $instance ) {
  $title = ! empty( $instance['title'] ) ? $instance['title'] : __( 'New title', 'text_domain' );
?>
  <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>
<?php
    }

    /**
     * Processing widget options on save
     *
     * @param array $new_instance The new options
     * @param array $old_instance The previous options
     */
public function update( $new_instance, $old_instance ) {
  $instance = array();
	$instance['title'] = ( ! empty( $new_instance['title'] ) ) ? strip_tags( $new_instance['title'] ) : '';

	return $instance;
}
}

add_action( 'widgets_init', function(){
    register_widget('vertige_mailchimp');
});