code: def build_pre_approval_payment_params(self, **kwargs):
          
  
          params = kwargs or {}
  
          params['reference'] = self.reference
          params['preApprovalCode'] = self.code
  
          for i, item in enumerate(self.items, 1):
              params['itemId%s' % i] = item.get('id')
              params['itemDescription%s' % i] = item.get('description')
              params['itemAmount%s' % i] = item.get('amount')
              params['itemQuantity%s' % i] = item.get('quantity')
              params['itemWeight%s' % i] = item.get('weight')
              params['itemShippingCost%s' % i] = item.get('shipping_cost')
  
          self.data.update(params)
          self.clean_none_params()
docs: build a dict with params