Basic payment provider settings form API

src/pretix/base/payment.py

@@ -1,10 +1,36 @@
+from pretix.base.settings import SettingsSandbox
+
+
 class BasePaymentProvider:
     """
     This is the base class for all payment providers.
     """
 
-    def get_identifier(self) -> str:
+    def __init__(self, event):
+        self.event = event
+        self.settings = SettingsSandbox('payment', self.identifier, event)
+
+    def __str__(self):
+        return self.identifier
+
+    @property
+    def verbose_name(self) -> str:
         """
-        Return a unique identifier for this payment provider
+        A human-readable name for this payment provider
+        """
+        raise NotImplementedError
+
+    @property
+    def identifier(self) -> str:
+        """
+        A unique identifier for this payment provider
+        """
+        raise NotImplementedError()
+
+    @property
+    def settings_form_fields(self) -> dict:
+        """
+        A dictionary. The keys should be (unprefixed) EventSetting keys,
+        the values should be corresponding django form fields
         """
         raise NotImplementedError()