Warning: mysqli_stmt_execute() expects exactly 1 parameter, 0 given in

if(isset($_POST['BtnSubmit'])){

    include_once 'dbConnection.php';



    if($conn -> connect_error) {

    die("connection failed:".$conn-> connect_error);
    }

$date           = $_POST['date'];
$select_bank    = $_POST['select_bank'];
$entry_type     = $_POST['entry_type'];
$income_cat     = $_POST['income_cat'];
$amount         = $_POST['amount'];


        $sql = "INSERT INTO wp_testdb (data_one, data_two, data_three, data_four, data_five) VALUES (?, ?, ?, ?, ?);";

        $stmt = mysqli_stmt_init($conn);

        if(!mysqli_stmt_prepare($stmt,$sql)) {

            echo "SQL Error !!";
        } else {

            mysqli_stmt_bind_param($stmt, "sssss", $date, $select_bank, $entry_type, $income_cat, $amount);
            mysqli_stmt_execute();

        }
}

<?php

$dbServername = "localhost";
$dbUsername = "root";
$dbPassword = "";
$dbName = "wordpress";

$conn= mysqli_connect($dbServername, $dbUsername, $dbPassword, $dbName);