toString method
A string representation of this object.
Some classes have a default textual representation,
often paired with a static parse function (like int.parse).
These classes will provide the textual representation as
their string representation.
Other classes have no meaningful textual representation
that a program will care about.
Such classes will typically override toString to provide
useful information when inspecting the object,
mainly for debugging or logging.
Implementation
@override
String toString() {
return '''
cardNumber: ${cardNumber},
cardholderName: ${cardholderName},
expiryDate: ${expiryDate},
cvv: ${cvv},
taxId: ${taxId},
brand: ${brand},
formVersion: ${formVersion},
cvvFieldVersion: ${cvvFieldVersion},
data: ${data},
isAmex: ${isAmex},
isEmpty: ${isEmpty}
''';
}