diff --git a/tsg/main.py b/tsg/main.py
index 9faa9e61d47f537e2bbfa0e43681d2c2bb6ba901..7cfa0d68552f1b24cb88a6381e6ad8b1cc0cdc99 100644
--- a/tsg/main.py
+++ b/tsg/main.py
@@ -318,7 +318,7 @@ class TranscriptGenerator:
 
         return inclusion_arr
 
-    def _get_unique_inclusions(self) -> tuple(list, np.array, np.array):
+    def _get_unique_inclusions(self) -> tuple[list, np.array, np.array]:
         """Inclusion of unique intron inclusion via arrays and counts and name generation of each unique count.
         
         Args: