Help me fix the error in the code connect$\_$error$)\{$

die$("$Connection failed: $".$ $conn$->$connect$\_$error$)$;

$\}$

$//$ Process form data when the form is submitted

if $($$$\_$SERVER$["$REQUEST$\_$METHOD"$]==$ "POST"$)\{$

$username $=$ $$\_$POST$[\text{'}$editUsername$\text{'}]$;

$name $=$ $$\_$POST$[\text{'}$editName$\text{'}]$;

$age $=$ $$\_$POST$[\text{'}$editAge$\text{'}]$;

$gender $=$ $$\_$POST$[\text{'}$editGender$\text{'}]$;

$dob $=$ $$\_$POST$[\text{'}$editDOB$\text{'}]$;

$height $=$ $$\_$POST$[\text{'}$editHeight$\text{'}]$;

$weight $=$ $$\_$POST$[\text{'}$editWeight$\text{'}]$;

$//$ Insert data into the HealthLevels table

$sql $=$ "INSERT INTO HealthLevels $($UserID$,$ Age, DateOfBirth, Height, Weight, BMI$)$

VALUES $(\text{'}$$username', $\text{'}$$age', $\text{'}$$dob', $\text{'}$$height', $\text{'}$$weight', $\text{'}\text{'})"$;

if $($$conn$->$query$($$sql$)===$ TRUE$)\{$

echo "Health level updated successfully";

$\}$ else $\{$

echo "Error updating health level: $".$ $conn$->$error;

$\}$

$\}$

$conn$->$close$()$;

$?>$