public static function uchr( $codes ) {

		// Single character code.
		if ( \is_scalar( $codes ) ) {
			$codes = \func_get_args(); // phpcs:ignore PHPCompatibility.FunctionUse.ArgumentFunctionsReportCurrentValue.NeedsInspection
		}

		// Deal with an array of character codes.
		$json = '"';
		foreach ( $codes as $code ) {
			$json .= \sprintf( '\u%04x', $code );
		}
		$json .= '"';

		return \json_decode( $json );
	}