serialize method
Serializes information the current object
writer Serialization writer to use to serialize this model
Implementation
@override
void serialize(SerializationWriter writer) {
writer.writeStringValue('brand', brand);
writer.writeStringValue('country', country);
writer.writeIntValue('exp_month', expMonth);
writer.writeIntValue('exp_year', expYear);
writer.writeStringValue('last4', last4);
writer.writeAdditionalData(additionalData);
}