def price_set(definition, order)
      if order.price != definition['set'][price_paid]
        log_order(order)
        log_error 'order matched but price differs; ignoring this order.'
        p order
        p definition
        return 0, 0
      else
        return definition['set']['half'], definition['set']['full']
      end
    end
def price_set(definition, order)
      if order.price != definition['set'][price_paid]
        log_order(order)
        log_error 'order matched but price differs; ignoring this order.'
        p order
        p definition
        return 0, 0
      else
        return definition['set']['half'], definition['set']['full']
      end
    end
Calculates the prices according to the `set` definition.