What is the purpose of the code snippet `if (!$_POST['gesendet'] && !$_POST['name'])` and why is it causing an "Undefined index" notice in PHP?

The code snippet `if (!$_POST['gesendet'] && !$_POST['name'])` is checking if the 'gesendet' and 'name' keys are not present in the $_POST superglobal array. The "Undefined index" notice is caused because PHP is trying to access keys that may not exist in the $_POST array. To solve this issue, you can use the `isset()` function to check if the keys exist before accessing them.

if (!isset($_POST['gesendet']) && !isset($_POST['name'])) {
    // Code block if 'gesendet' and 'name' keys are not present
}