old_contents: from decimal import Decimal as D
  from django.template.loader import render_to_string
  from django.utils.translation import ugettext_lazy as _
  
  from oscar.apps.shipping import methods
  from oscar.core import prices
  
  class SelfPickup(methods.Free):
      """
      This shipping method specifies that goods can be picked up by customer.
      For free, of course
      """
      charge_incl_tax = None
      code = 'self-pickup'
      name = _('Self-service Pickup and shipping')
      description = _('Customers can pick up goods in the central store')
  
new_contents: from decimal import Decimal as D
  from django.template.loader import render_to_string
  from django.utils.translation import ugettext_lazy as _
  
  from oscar.apps.shipping import methods
  from oscar.core import prices
  
  class SelfPickup(methods.Free):
      """
      This shipping method specifies that goods can be picked up by customer.
      For free, of course
      """
      charge_incl_tax = None
      code = 'self-pickup'
      name = _('Self-service Pickup and shipping')
      description = _('Customers can pick up goods in the central store')
      def calculate(self, basket, shipping_address=None):
          # This method exists just to drop additional args
          return super(SelfPickup, self).calculate(basket)
subject: Fix SelfPickup calculate method