it is possible to have variation with multiple base

application/contribution in payroll, remove the asserts

product/ERP5/mixin/amount_generator.py

@@ -289,7 +289,6 @@ class AmountGeneratorMixin:
                                                   if x[:12] != 'base_amount/']))
         if variation_category_list:
           base_application_set.difference_update(variation_category_list)
-          assert len(base_application_set) == 1
         # property_dict may include
         #   resource - VAT service or a Component in MRP
         #              (if unset, the amount will only be used for reporting)
@@ -356,7 +355,6 @@ class AmountGeneratorMixin:
                                                   if x[:12] != 'base_amount/']))
         if variation_category_list:
           base_contribution_set.difference_update(variation_category_list)
-          assert len(base_contribution_set) == 1
         for base_contribution in base_contribution_set:
           base_amount.contribute(base_contribution, variation_category_list,
                                  quantity)