<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def UpdateBudget(self, client_customer_id, budget_id, micro_amount, delivery_method):
 """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. """

    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)