WP_Widget_Media::form( array $instance )

	final public function form( $instance ) {
		$instance_schema = $this->get_instance_schema();
		$instance = wp_array_slice_assoc(
			wp_parse_args( (array) $instance, wp_list_pluck( $instance_schema, 'default' ) ),
			array_keys( $instance_schema )
		);

		foreach ( $instance as $name => $value ) : ?>
			<input
				type="hidden"
				data-property="<?php echo esc_attr( $name ); ?>"
				class="media-widget-instance-property"
				name="<?php echo esc_attr( $this->get_field_name( $name ) ); ?>"
				id="<?php echo esc_attr( $this->get_field_id( $name ) ); // Needed specifically by wpWidgets.appendTitle(). ?>"
				value="<?php echo esc_attr( is_array( $value ) ? join( ',', $value ) : strval( $value ) ); ?>"
			/>
		<?php
		endforeach;
	}