what im trying to do is, if i were to type the function as br(); without any arguments i want the output to display my own message instead of php's error being

Warning: Missing argument 1 for br()


<?php

function br($num)
{
$num = 0;
if ($num == null) { die('br function must contain a value');
return;
}

else { echo "<br>"; }
return;
}


br();
?>

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