Use OrderedSet as default set_class

Author: lafrech

src/marshmallow/schema.py

@@ -315,6 +315,8 @@ class AlbumSchema(Schema):
 
     OPTIONS_CLASS = SchemaOpts  # type: type
 
+    set_class = OrderedSet
+
     # These get set by SchemaMeta
     opts = None  # type: SchemaOpts
     _declared_fields = {}  # type: typing.Dict[str, ma_fields.Field]
@@ -411,10 +413,6 @@ def __repr__(self) -> str:
     def dict_class(self) -> type:
         return OrderedDict if self.ordered else dict
 
-    @property
-    def set_class(self) -> type:
-        return OrderedSet if self.ordered else set
-
     @classmethod
     def from_dict(
         cls,