Write code to reverse a string without using built-in functions.
Implement reverse_string(s) and return a new string containing the characters of s in reverse order. Do not use reversed(), slicing, .reverse(), or .join().
The input is a string, and the output must be a string. Preserve spaces, punctuation, character case, and Unicode characters.
s contains Unicode characters, spaces, and punctuationreversed(), slicing, .reverse(), or .join()def reverse_string(s):