This class represents an unknown payment method.
This class will only be created as part of a response or error response. Specifically, this class will only be created if Braintree responds with a payment method this SDK does not know how to handle.
Because this SDK does not know how to handle this, the class will have very limited functionality relative to the other payment methods.
This returns the account's customer's ID.
This returns if this account is default.
is_default() is an alias for this attribute.
This returns the account's token.
This returns the "unknown payment methods" image URL. This is a URL provided by and hosted by Braintree.