Correct code local cash Gravatars with plugin “FV Gravatar Cache”

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This code was written to me ChatGPT

// 91. Comment Author Gravatar URL
if( ! function_exists('ampforwp_get_comments_gravatar') ){
	function ampforwp_get_comments_gravatar( $comment ) {
		global $redux_builder_amp;
		if(isset($redux_builder_amp['ampforwp-display-avatar']) && $redux_builder_amp['ampforwp-display-avatar'] == 0){
			return '';
		}
		if (class_exists('FV_Gravatar_Cache')) {
			$options = get_option('fv_gravatar_cache');
			$size = !empty($options['size']) ? $options['size'] : '96';
			$email_hash = md5(strtolower(trim($comment->comment_author_email)));
			$upload_dir = wp_upload_dir(); 
			$cache_dir = $upload_dir['basedir'] . '/fv-gravatar-cache/';
			$cache_url = $upload_dir['baseurl'] . '/fv-gravatar-cache/';

			
			$cached_avatar_path = $cache_dir . $email_hash . 'x' . $size . '.png';
			$default_avatar_url = $cache_url . 'mystery' . esc_html($size) . '.png';

			if (file_exists($cached_avatar_path)) {
				$avatar_url = $cache_url . $email_hash . 'x' . $size . '.png';
			} else {
				$avatar_url = $default_avatar_url;
			}

			return $avatar_url;
		}

		$gravatar_exists = ampforwp_gravatar_checker($comment->comment_author_email);

		if (null !== ampforwp_get_wp_user_avatar($comment, 'comment')) {
			return ampforwp_get_wp_user_avatar($comment, 'comment');
		} elseif ($gravatar_exists) {
			return get_avatar_url($comment, apply_filters('ampforwp_get_comments_gravatar', '60'), '');
		} else {
			return apply_filters('ampforwp_get_comments_gravatar', '');
		}
	}
}