add more detailed description of collect_potential_discounts parameter

src/pretix/base/models/discount.py

@@ -337,6 +337,7 @@ class Discount(LoggedModel):
 
         :param positions: Dictionary mapping IDs to PositionInfo tuples.
                           Bundled positions may not be included.
+        :param collect_potential_discounts: For detailed description, see pretix.base.services.pricing.apply_discounts
 
         :return: A dictionary mapping keys from the input dictionary to new prices. All positions
                  contained in this dictionary are considered "consumed" and should not be considered

src/pretix/base/services/pricing.py

@@ -167,8 +167,12 @@ def apply_discounts(event: Event, sales_channel: Union[str, SalesChannel],
     :param sales_channel: Sales channel the cart was created with
     :param positions: Tuple of the form ``(item_id, subevent_id, line_price_gross, is_addon_to, is_bundled, voucher_discount)``
     :param collect_potential_discounts: If a `defaultdict(list)` is supplied, all discounts that could be applied to the cart
-    based on the "consumed" items, but lack matching "benefitting" items will be collected in it.
-    
+    based on the "consumed" items, but lack matching "benefitting" items will be collected therein.
+    The dict will contain a mapping from index in the `positions` list of the item that could be consumed, to a list
+    of tuples describing the discounts that could be applied in the form (discount, max_count, grouping_id).
+    max_count is either the maximum number of benefitting items that the discount would apply to, or `inf` if that number
+    is not limited. The grouping_id can be used to distinguish several occurrences of the same discount.
+
     :return: A list of ``(new_gross_price, discount)`` tuples in the same order as the input
     """
     if isinstance(sales_channel, SalesChannel):