diff --git a/registrasion/reporting/reports.py b/registrasion/reporting/reports.py
index 17f24dc4..36e11942 100644
--- a/registrasion/reporting/reports.py
+++ b/registrasion/reporting/reports.py
@@ -43,16 +43,16 @@ class Report(object):
         return self._data
 
 
-def report_view(title, form_type):
+def report_view(title, form_type=None):
     ''' Decorator that converts a report view function into something that
     displays a Report.
 
     Arguments:
         title (str):
             The title of the report.
-        form_type (forms.Form or None):
-            A form class that can make this report display things. If None,
-            no form will be displayed.
+        form_type (Optional[forms.Form]):
+            A form class that can make this report display things. If not
+            supplied, no form will be displayed.
 
     '''
 
diff --git a/registrasion/staff_views.py b/registrasion/staff_views.py
index 4bedf3d1..a21e663b 100644
--- a/registrasion/staff_views.py
+++ b/registrasion/staff_views.py
@@ -46,7 +46,7 @@ def reports_list(request):
 # Report functions
 
 
-@report_view("Paid items", forms.ProductAndCategoryForm)
+@report_view("Paid items", form_type=forms.ProductAndCategoryForm)
 def items_sold(request, form):
     ''' Summarises the items sold and discounts granted for a given set of
     products, or products from categories. '''
@@ -92,7 +92,7 @@ def items_sold(request, form):
     return Report("Paid items", headings, data)
 
 
-@report_view("Inventory", forms.ProductAndCategoryForm)
+@report_view("Inventory", form_type=forms.ProductAndCategoryForm)
 def inventory(request, form):
     ''' Summarises the inventory status of the given items, grouping by
     invoice status. '''