List the caller's cached payment methods

[  {    "brand": "string",    "created_at": "2019-08-24T14:15:22Z",    "exp_month": 0,    "exp_year": 0,    "id": "497f6eca-6276-4993-bfeb-53cbbbba6f08",    "is_default": true,    "kind": "card",    "last4": "string",    "vendor_type": "stripe"  }]

{  "detail": "Pool slug must be unique.",  "instance": "urn:forestvpn:trace:a1b2c3d4",  "title": "Validation Error",  "type": "https://fvpn.net/errors/validation"}