I'm currently working on a project where I need to manipulate dates using PHP. I came across a function called `date_sub()` and I'm not entirely sure how it works. I have tried looking at the PHP documentation, but I'm having a hard time understanding it.
Could someone please explain to me how the `date_sub()` function works and provide an example of how to use it? I would really appreciate it if you could also provide some personal context to help me better understand.
Thank you in advance for your help!