--- a/taskcluster/taskgraph/task/transform.py
+++ b/taskcluster/taskgraph/task/transform.py
@@ -83,18 +83,18 @@ class TransformTask(base.Task):
     def get_dependencies(self, taskgraph):
         return [(label, name) for name, label in self.dependencies.items()]
 
     def optimize(self, params):
         if 'files-changed' in self.when:
             changed = files_changed.check(
                 params, self.when['files-changed'])
             if not changed:
-                logger.debug('no files found matching a pattern in `when.files-changed` for '
-                             + self.label)
+                logger.debug('no files found matching a pattern in `when.files-changed` for ' +
+                             self.label)
                 return True, None
         return False, None
 
     @classmethod
     def from_json(cls, task_dict):
         # when reading back from JSON, we lose the "when" information
         task_dict['when'] = {}
         return cls(task_dict['attributes']['kind'], task_dict)