toMap method
Implementation
Map<String, dynamic> toMap() {
return {
'last4_digits': last4Digits,
'card_number': cardNumber,
'expiry_month': expiryMonth,
'expiry_year': expiryYear,
'card_holder_name': cardHolderName,
'nick_name': nickName,
'card_brand': cardBrand,
};
}