Create a function that converts a given string's characters into their respective hexadecimal ASCII values.
Create a Python function that converts ASCII characters in a string to their hexadecimal representations. The ASCII (American Standard Code for Information Interchange) system assigns unique integer values to characters. Python's built-in functions like `ord()` can be used to obtain a character's ASCII integer, and `hex()` can convert this integer to hexadecimal. The function you create should accept a string and return a new string, in which each original character is replaced by its hexadecimal ASCII value. In the output string, hexadecimal values should be separated by a space. ### Parameters - `txt` (str): The string to be converted into hexadecimal ASCII values. ### Returns - (str): A new string where each original character is replaced by its hexadecimal ASCII value. Hexadecimal values are separated by a space. ### Examples ```python # 'h' => 68, 'e' => 65, 'l' => 6c, 'l' => 6c, 'o' => 6f, ' ' => 20, 'w' => 77, 'o' => 6f, 'r' => 72, 'l' => 6c, 'd' => 64 ascii_to_hex("hello world") # Returns: "68 65 6c 6c 6f 20 77 6f 72 6c 64" ```