public static function is_valid_user_token( $token ) {
		/**
		 * @var mixed $value
		 * @var array $pieces
		 * @var int $recip_id
		 * @var array $trigger_data
		 * @var int $user_id
		 * @var array $replace_args
		 */
		extract( $token ); // phpcs:ignore WordPress.PHP.DontExtract.extract_extract

		if ( ! $pieces ) {
			// Token array is empty.
			return false;
		}
		$replaceable = str_replace( array( '{{', '}}', '', $pieces ) );
		if ( ! in_array( $replaceable, self::$user_tokens, false ) ) {
			// Token is missing.
			return false;
		}

		return true;
	}