curl --request GET \
  --url https://api.satsuma.ai/payment-method \
  --header 'Authorization: <api-key>'

{
  "data": [
    {
      "id": "<string>",
      "type": "<string>",
      "card": {
        "brand": "<string>",
        "last4": "<string>",
        "exp_month": 123,
        "exp_year": 123
      }
    }
  ],
  "messages": [
    {
      "context": "<string>",
      "text": "<string>",
      "data": {}
    }
  ]
}