fix(api.py): update filter logic to apply filters as OR operation

Refactor filter application to allow combining multiple filters
using an OR operation. This change ensures that classes meeting
any of the filter criteria are included. Additionally, remove
duplicates and sort the resulting classes by start time and name
for consistent output.

src/otf_api/api.py

@@ -203,8 +203,8 @@ def get_classes(
             exclude_cancelled (bool): Whether to exclude classes that were cancelled by the studio. Default is True.
             exclude_unbookable (bool): Whether to exclude classes that are outside the scheduling window. Default is\
             True.
-            filters (list[ClassFilter] | ClassFilter | None): A list of filters to apply to the classes. Filters are\
-            applied in the order they are provided. Default is None.
+            filters (list[ClassFilter] | ClassFilter | None): A list of filters to apply to the classes, or a single\
+            filter. Filters are applied as an OR operation. Default is None.
 
         Returns:
             OtfClassList: The classes for the user.
@@ -246,11 +246,17 @@ def get_classes(
             classes_list.classes = classes_list.classes[:limit]
 
         if filters:
+            filtered_classes: list[models.OtfClass] = []
+
             if not isinstance(filters, list):
                 filters = [filters]
 
             for f in filters:
-                classes_list.classes = f.filter_classes(classes_list.classes)
+                filtered_classes.extend(f.filter_classes(classes_list.classes))
+
+            # remove duplicates
+            classes_list.classes = list({c.class_uuid: c for c in filtered_classes}.values())
+            classes_list.classes = sorted(classes_list.classes, key=lambda x: (x.starts_at_local, x.name))
 
         return classes_list