$checks[ $plugin->get_id() ] = $plugin->get_name();
			} elseif ( ! $is_using_cdn && $plugin->is_serving_webp() ) {
				$checks[ $plugin->get_id() ] = $plugin->get_name();
			}
		}

		return $checks;
	}

	/**
	 * Get a list of active plugins that convert and/or serve webp images.
	 *
	 * @since  3.4
	 * @access private
	 * @author Grégory Viguier
	 *
	 * @return array An array of Webp_Interface objects.
	 */
	private function get_webp_plugins() {
		/**
		 * Add Webp plugins.
		 *
		 * @since  3.4
		 * @author Grégory Viguier
		 *
		 * @param array $webp_plugins An array of Webp_Interface objects.
		 */
		$webp_plugins = (array) apply_filters( 'rocket_webp_plugins', [] );

		if ( ! $webp_plugins ) {
			// Somebody probably messed up.
			return [];
		}

		foreach ( $webp_plugins as $i => $plugin ) {
			if ( ! is_a( $plugin, '\WP_Rocket\Subscriber\Third_Party\Plugins\Images\Webp\Webp_Interface' ) ) {
				unset( $webp_plugins[ $i ] );
				continue;
			}
			if ( ! $this->is_plugin_active( $plugin->get_basename() ) ) {
				unset( $webp_plugins[ $i ] );
				continue;
			}
		}

		return $webp_plugins;
	}

	/**
	 * Tell if a plugin is active.
	 *
	 * @since  3.4
	 * @access public
	 * @see    \plugin_basename()
	 * @author Grégory Viguier
	 *
	 * @param  string $plugin_basename A plugin basename.
	 * @return bool
	 */
	private function is_plugin_active( $plugin_basename ) {
		if ( \doing_action( 'deactivate_' . $plugin_basename ) ) {
			return false;
		}

		if ( \doing_action( 'activate_' . $plugin_basename ) ) {
			return true;
		}

		return \rocket_is_plugin_active( $plugin_basename );
	}

	/**
	 * Tell if WP Rocket uses a CDN for images.
	 *
	 * @since  3.4
	 * @access private
	 * @author Grégory Viguier
	 *
	 * @return bool
	 */
	private function is_using_cdn() {
		// Don't use `$this->options_data->get( 'cdn' )` here, we need an up-to-date value when the CDN option changes.
		$use = get_rocket_option( 'cdn' ) && $this->cdn_subscriber->get_cdn_hosts( [], [ 'all', 'images' ] );
		/**
		 * Filter whether WP Rocket is using a CDN for webp images.
		 *
		 * @since  3.4
		 * @author Grégory Viguier
		 *
		 * @param bool $use True if WP Rocket is using a CDN for webp images. False otherwise.
		 */
		return (bool) apply_filters( 'rocket_webp_is_using_cdn', $use );
	}
}
<br />
<b>Fatal error</b>:  Uncaught Error: Call to a member function withArgument() on null in /home/payon/public_html/wp-content/plugins/wp-rocket/inc/classes/ServiceProvider/class-common-subscribers.php:73
Stack trace:
#0 /home/payon/public_html/wp-content/plugins/wp-rocket/vendor/league/container/src/ServiceProvider/ServiceProviderAggregate.php(84): WP_Rocket\ServiceProvider\Common_Subscribers-&gt;register()
#1 /home/payon/public_html/wp-content/plugins/wp-rocket/vendor/league/container/src/Container.php(88): League\Container\ServiceProvider\ServiceProviderAggregate-&gt;register('cdn_subscriber')
#2 /home/payon/public_html/wp-content/plugins/wp-rocket/inc/classes/class-plugin.php(186): League\Container\Container-&gt;get('cdn_subscriber')
#3 /home/payon/public_html/wp-content/plugins/wp-rocket/inc/main.php(40): WP_Rocket\Plugin-&gt;load()
#4 /home/payon/public_html/wp-includes/class-wp-hook.php(308): rocket_init('')
#5 /home/payon/public_html/wp-includes/class-wp-hook.php(332): WP_Hook-&gt;apply_filters(NULL, Array)
#6 /home/payon/public_html/wp-in in <b>/home/payon/public_html/wp-content/plugins/wp-rocket/inc/classes/ServiceProvider/class-common-subscribers.php</b> on line <b>73</b><br />