Фатальная ошибка: вызов неопределенной функции valid() в C:\xampp\htdocs\sites\admin_panel\student_center_system\controller\admin\editmaster.php на линии 69

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Это и есть editmaster.php что это за ошибка и я думаю, что все хорошо определено .кто-нибудь мне поможет.

Что я уже пробовал:

<?php session_start();
    include("../dbConfig.php");
    include "navigation.php";
    include "header.php";
    include "footer.php";

{

} 
	            $item_id = '';
				$item_name = '';
				$description = '';
				$item_category = '';
				$pic = '';
				if (isset($_POST['updateitem']))
				{

				    if (is_numeric($_POST['item_id']))
				{

					$item_id = $_POST['item_id'];
					$item_name = mysql_real_escape_string(htmlspecialchars($_POST['item_name']));
					$description = mysql_real_escape_string(htmlspecialchars($_POST['description']));
					$item_category = mysql_real_escape_string(htmlspecialchars($_POST['item_category']));
					$pic = mysql_real_escape_string(htmlspecialchars($_POST['pic']));

				if ($item_name == '' || $description == '' || $item_category == '' || $pic == '')
				{

				$error = 'ERROR: Please fill in all required fields!';

				valid($item_id, $item_name, $description, $item_category, $pic, $error);
				}
				else
				{

				mysql_query("UPDATE lost_items_table SET item_name = '$item_name', description = '$description', item_category = '$item_category', pic = '$pic' WHERE item_id = '$item_id'")
				or die(mysql_error());

				header("Location: viewitems.php");
				}
				}
				else
				{

				echo 'Error!';
				}
				}
				else

				{

				if (isset($_GET['item_id']) && is_numeric($_GET['item_id']) && $_GET['item_id'] > 0)
				{

				$item_id = $_GET['item_id'];
				$result = mysql_query("SELECT * FROM lost_items_table WHERE item_id=$item_id")
				or die(mysql_error());
				$result1 = mysql_fetch_array($result);

				if($result1)
				{

				$item_name = $result1['item_name'];
				$description = $result1['description'];
				$item_category = $result1['item_category'];
				$pic = $result1['pic'];

				valid($item_id, $item_name, $description, $item_category, $pic,'');
				}
				else
				{
				echo "No results!";
				}
				}
				else

				{
				echo 'Error!';
				}
}

?>


					
	   <!-- Page Content -->
        <div id="page-wrapper">
            <div class="container-fluid">	            
					            <!-- /.row -->
					            <div class="row">
					                <!--div class="col-md-8 col-md-offset-4"-->
					                <div class="col-lg-6">
					                    <div class="Register-panel panel panel-default">
					                    <!--div class="panel panel-default"-->
					                        <div class="panel-heading">
					                            Edit Item
					                        </div>
					                        <div class="panel-body">
					                            <div class="row">
					                                <div class="col-lg-6">
					                                	<div class="panel-body">
						                            		<form role="form" action="adminPage.php">
						                            					<input type="text" name="item_id" value=<?php echo $item_id; ?> readonly><br>
						                            					<input type="text" name="item_name" required autofocus placeholder="Item-Name" value=<?php echo $item_name; ?>><br>
						                            					<input type="text" name="description" required autofocus placeholder="Description" value=<?php echo $description; ?>><br>
						                            					<input type="text" name="item_category" required autofocus placeholder="Item_category" value=<?php echo $item_category; ?>><br>
						                            					<input type="text" name="pic" required autofocus placeholder="pic" value=<?php echo $pic; ?>><br>

						                            					<input type="submit" name="updateitemBtn" value="Update">
						                            		</form>
						                                </div>
					                                </div>
					                                <!-- /.col-lg-6 (nested) -->
					                            </div>
					                            <!-- /.row (nested) -->
					                        </div>
					                        <!-- /.panel-body -->
					                    </div>
					                    <!-- /.panel -->
					                </div>
					                <!-- /.col-lg-12 -->
					            </div>
					            <!-- /.row -->
			</div>
            <!-- /.container-fluid -->
        </div>
        <!-- /#page-wrapper -->

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