Błąd... Co i jak? renderForm, problem z funkcja renderForm Opcje

[Waloch016]

Mam problem cały czas pokazuje mi łąd że błędne zapytanie do niezdefiniowanej funkji render form. w linji 79

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 <?php /*
 
           EDIT RECORD
 
        */
	// if the 'id' variable is set in the URL, we know that we need to edit a record
 
	include('db.php');
 
	if (isset($_GET['id']))
	{
		// if the form's submit button is clicked, we need to process the form
		if (isset($_POST['submit']))
		{
			// make sure the 'id' in the URL is valid
			if (is_numeric($_POST['id']))
			{
				// get variables from the URL/form
 
				$car = $_POST['car'];
				$date = $_POST['date'];
				$time = $_POST['time'];
				$number = $_POST['number'];
				$name = $_POST['name'];
				$type = $_POST['type'];
				$price = $_POST['price'];
 
				// check that firstname and lastname are both not empty
				if ($car == '' || $date == '' || $time == '' || $number == '' || $name == '' || $type =='' || $price == '')
				{
					// if they are empty, show an error message and display the form
					$error = 'ERROR: Please fill in all required fields!';
					renderForm($car, $date, $time, $number, $name, $type, $price, $error, $id);
				}
				else
				{
					// if everything is fine, update the record in the database
					if ($stmt = $conn->prepare("UPDATE `booking` SET car = ?, date = ?, time = ?, number = ?, name = ?, type = ?, price = ?
						WHERE id=?"))
					{
						$stmt->bind_param("sssi", $car, $date, $time, $number, $name, $type, $price, $id);
						$stmt->execute();
						$stmt->close();
					}
					// show an error message if the query has an error
					else
					{
						echo "ERROR: could not prepare SQL statement.";
					}
 
					// redirect the user once the form is updated
					header("Location: booking.php");
				}
			}
			// if the 'id' variable is not valid, show an error message
			else
			{
				echo "Error!";
			}
		}
		// if the form hasn't been submitted yet, get the info from the database and show the form
		else
		{
			// make sure the 'id' value is valid
 
				// get 'id' from URL
				$id = $_GET['id'];
 
				// get the recod from the database
				if($stmt = $conn->prepare("SELECT * FROM `booking` WHERE id=?"))
				{
					$stmt->bind_param("i", $id);
					$stmt->execute();
 
					$stmt->bind_result($car, $date, $time, $number, $name, $type, $price, $id);
					$stmt->fetch();
 
					// show the form
					renderForm($car, $date, $time, $number, $name, $type, $price, NULL, $id);	
					$conn->close();
				}
				// show an error if the query has an error
				else
				{
					echo "Error: could not prepare SQL statement";
				}
 
			// if the 'id' value is not valid, redirect the user back to the view.php page
 
			header("Location: booking.php");
 
		}
	}
 
?>
 
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