diff --git a/panoptica/panoptica_aggregator.py b/panoptica/panoptica_aggregator.py
index 6460d6d..03beb25 100644
--- a/panoptica/panoptica_aggregator.py
+++ b/panoptica/panoptica_aggregator.py
@@ -22,7 +22,7 @@ class Panoptica_Aggregator:
     def __init__(
         self,
         panoptica_evaluator: Panoptica_Evaluator,
-        output_file: Path,
+        output_file: Path | str,
         continue_file: bool = True,
     ):
         """
@@ -36,6 +36,8 @@ def __init__(
         self.__output_buffer_file = None
         self.__evaluation_metrics = panoptica_evaluator.resulting_metric_keys
 
+        if isinstance(output_file, str):
+            output_file = Path(output_file)
         # uses tsv
         assert (
             output_file.parent.exists()
diff --git a/panoptica/panoptica_evaluator.py b/panoptica/panoptica_evaluator.py
index cb6c46a..36ec399 100644
--- a/panoptica/panoptica_evaluator.py
+++ b/panoptica/panoptica_evaluator.py
@@ -158,6 +158,9 @@ def segmentation_class_groups_names(self) -> list[str]:
             return [NO_GROUP_KEY]
         return self.__segmentation_class_groups.keys()
 
+    def _set_instance_matcher(self, matcher: InstanceMatchingAlgorithm):
+        self.__instance_matcher = matcher
+
     @property
     def resulting_metric_keys(self) -> list[str]:
         if self.__resulting_metric_keys is None: