Write a function that can be used to reverse a string in php

reverse_string.php

<?php
function reverse_string($str)  : string
{

	if(!is_string($str)) return "not a string";
	
	$lengthString = strlen($str);
	
	$data = [];
	
	for($i = ($lengthString -1); $i >=0; $i--){
		
		$data[] = $str[$i];
	   
	}
	
	return implode("", $data);
}


print_r(reverse_string("John Peich"));