Using `require once()`

# Mastering PHP File Inclusion: Using `require_once()` for Robust Code Have you ever encountered a situation where your PHP code throws errors because a function or a class is defined multiple times? Or maybe you're concerned about the performance impact of repeatedly including the same file? The `require_once()` function in PHP is your powerful ally in preventing these common pitfalls. This function ensures that a file is included only *once* during the execution of your script, regardless o