Creating an Invoice

HashMap<String, Object> invoiceData = new HashMap<>();
invoiceData.put("customer_id", 29);  // Customer ID
invoiceData.put("date", "2024-01-15");  // Invoice date
invoiceData.put("line_items", Arrays.asList(
    new HashMap<String, Object>() {{
        put("item_name", "Consulting Service");
        put("item_price", 200.00);
        put("quantity", 5);
    }}
));

int invoiceId = co.create(ChargeOver.Target.INVOICE, invoiceData);
if (invoiceId < 0) {
    System.out.println(co.getLastError());
} else {
    System.out.println("Created Invoice ID: " + invoiceId);
}