diff --git a/python/podio_class_generator.py b/python/podio_class_generator.py
index 4420e4345..f3dd7bc04 100755
--- a/python/podio_class_generator.py
+++ b/python/podio_class_generator.py
@@ -384,7 +384,8 @@ def _instantiate_associations(self):
 
     if self.upstream_edm:
       ext_datatypes = [DataType(d) for d in self.upstream_edm.datatypes]
-      includes.extend([self._build_include_for_class(f'{d.bare_type}Collection', IncludeFrom.EXTERNAL) for d in ext_datatypes])
+      includes.extend([self._build_include_for_class(f'{d.bare_type}Collection',
+                                                     IncludeFrom.EXTERNAL) for d in ext_datatypes])
 
       combinations += tuple(product(ext_datatypes, datatypes))