Small simplification

coin/billing/admin.py

@@ -198,11 +198,9 @@ class PaymentAdmin(admin.ModelAdmin):
     form = autocomplete_light.modelform_factory(Payment, fields='__all__')
 
     def get_readonly_fields(self, request, obj=None):
-        if not obj:
-            return self.readonly_fields
 
         # If payment already started to be allocated or already have a member
-        if obj.amount_already_allocated != 0 or obj.member != None:
+        if obj and (obj.amount_already_allocated != 0 or obj.member != None):
             # All fields are readonly
             return flatten_fieldsets(self.declared_fieldsets)
         else: