Unable to use PayPal Express (HEAD) with OrderAndItemCharges shipping method about django-oscar-paypal HOT 3 CLOSED

def basket_charge_incl_tax(self):
    warnings.warn((
        "Use the charge_incl_tax property not basket_charge_incl_tax. "
        "Basket.basket_charge_incl_tax will be removed "
        "in v0.7"),
        DeprecationWarning)
    return self.charge_incl_tax

# For backwards compatibility, keep an alias called "ShippingMethod"
ShippingMethod = Base

class ShippingMethod(models.Model):
.....

class OrderAndItemCharges(ShippingMethod):
...

@property
def charge_incl_tax(self):
    """
    Return basket total including tax
    """
    if self.free_shipping_threshold is not None and \
            self._basket.total_incl_tax >= self.free_shipping_threshold:
        return D('0.00')

    charge = self.price_per_order
    for line in self._basket.lines.all():
        charge += line.quantity * self.price_per_item
    return charge