A tokenized, reusable payment method saved against a Sumup.Customer.
Sumup.Customer
@type t() :: %Sumup.PaymentInstrument{ active: boolean(), card_last_4_digits: String.t() | nil, card_type: String.t() | nil, created_at: DateTime.t() | nil, mandate: map() | nil, raw: map(), token: String.t(), type: String.t() | nil }