code: def UpdateBudget(self, client_customer_id, budget_id, micro_amount,
                     delivery_method):
      
      self.client.SetClientCustomerId(client_customer_id)
      operations = [{
          'operator': 'SET',
          'operand': {
              'budgetId': budget_id,
              'amount': {
                  'microAmount': micro_amount
              },
              'deliveryMethod': delivery_method
          }
      }]
      self.client.GetService('BudgetService').mutate(operations)
docs: Update a Budget with the given budgetId.
  
      Args:
        client_customer_id: str Client Customer Id used to update Budget.
        budget_id: str Id of the budget to be updated.
        micro_amount: str New value for the microAmount field.
        delivery_method: str New value for the deliveryMethod field.