Programmatically create order, add (variative) products from cart to it, change status to `processing` and empty cart. Wordpress, WooCommerce 2.4.

create_order.php

  $address = array(
    'first_name' => $customer_name,
    'last_name'  => '',
    'company'    => '',
    'email'      => $customer_email,
    'phone'      => $customer_phone,
    'address_1'  => '',
    'address_2'  => '',
    'city'       => '',
    'state'      => '',
    'postcode'   => '',
    'country'    => ''
  );

  $order = wc_create_order();

  // add products from cart to order
  $items = WC()->cart->get_cart();
  foreach($items as $item => $values) {
    $product_id = $values['product_id'];
    $product = wc_get_product($product_id);
    $var_id = $values['variation_id'];
    $var_slug = $values['variation']['attribute_pa_weight'];
    $quantity = (int)$values['quantity'];
    $variationsArray = array();
    $variationsArray['variation'] = array(
      'pa_weight' => $var_slug
    );
    $var_product = new WC_Product_Variation($var_id);
    $order->add_product($var_product, $quantity, $variationsArray);
  }

  $order->set_address( $address, 'billing' );
  $order->set_address( $address, 'shipping' );

  $order->calculate_totals();
  $order->update_status( 'processing' );

  WC()->cart->empty_cart();

Got error like

Fatal error: Uncaught Error: Call to a member function empty_cart() on null in /var/www/html/live/something....................;

Any solution?