diff --git a/altamisa/isatab/modify_investigation.py b/altamisa/isatab/modify_investigation.py
index 42e6c91..677ad19 100644
--- a/altamisa/isatab/modify_investigation.py
+++ b/altamisa/isatab/modify_investigation.py
@@ -5,7 +5,7 @@
 from altamisa.isatab import InvestigationReader
 
 
-class InvestigationForge():
+class InvestigationForge:
     """
     Provides methods to add assays to an existing investigation.