Add /payment/method field

Add new /payment/method enum field to specify the payment method
associated with the transaction. Valid values are bank_debit,
bank_redirect, bank_transfer, buy_now_pay_later, card, crypto,
digital_wallet, gift_card, real_time_payment, and rewards.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: horgh

HISTORY.rst

@@ -13,6 +13,8 @@ History
   validation.
 * Added the input ``/event/party``. This is the party submitting the
   transaction.
+* Added the input ``/payment/method``. This is the payment method associated
+  with the transaction.
 
 3.1.0 (2025-05-23)
 ++++++++++++++++++

README.rst

@@ -210,6 +210,7 @@ Score, Insights and Factors Example
     >>>     'payment': {
     >>>         'decline_code': 'invalid number',
     >>>         'was_authorized': False,
+    >>>         'method': 'card',
     >>>         'processor': 'stripe'
     >>>     },
     >>>     'shopping_cart': [{

src/minfraud/validation.py

@@ -98,6 +98,21 @@ def _hostname(hostname: str) -> str:
 
 _shipping_address["delivery_speed"] = _delivery_speed
 
+_payment_method = In(
+    [
+        "bank_debit",
+        "bank_redirect",
+        "bank_transfer",
+        "buy_now_pay_later",
+        "card",
+        "crypto",
+        "digital_wallet",
+        "gift_card",
+        "real_time_payment",
+        "rewards",
+    ],
+)
+
 _payment_processor = In(
     [
         "adyen",
@@ -320,6 +335,7 @@ def _uri(s: str) -> str:
         },
         "billing": _address,
         "payment": {
+            "method": _payment_method,
             "processor": _payment_processor,
             "was_authorized": bool,
             "decline_code": str,

tests/data/full-transaction-request.json

@@ -42,6 +42,7 @@
     "delivery_speed": "same_day"
   },
   "payment": {
+    "method": "card",
     "processor": "stripe",
     "was_authorized": false,
     "decline_code": "invalid number"

tests/test_validation.py

@@ -378,6 +378,23 @@ def test_referrer_uri(self) -> None:
 
 
 class TestPayment(ValidationBase, unittest.TestCase):
+    def test_method(self) -> None:
+        for good in (
+            "bank_debit",
+            "bank_redirect",
+            "bank_transfer",
+            "buy_now_pay_later",
+            "card",
+            "crypto",
+            "digital_wallet",
+            "gift_card",
+            "real_time_payment",
+            "rewards",
+        ):
+            self.check_transaction({"payment": {"method": good}})
+        for bad in ("bad", 1, ""):
+            self.check_invalid_transaction({"payment": {"method": bad}})
+
     def test_processor(self) -> None:
         for good in ("adyen", "stripe"):
             self.check_transaction({"payment": {"processor": good}})