diff --git a/metrik/flows/libor_flow.py b/metrik/flows/libor_flow.py
index 3ef4e01..37f843c 100644
--- a/metrik/flows/libor_flow.py
+++ b/metrik/flows/libor_flow.py
@@ -1,10 +1,10 @@
-from luigi import Task, DateParameter, LocalTarget
+from luigi import WrapperTask, DateParameter, LocalTarget
 
 from metrik.tasks.ice import LiborRateTask
 from metrik.targets.temp_file import TempFileTarget
 
 
-class LiborFlow(Task):
+class LiborFlow(WrapperTask):
     date = DateParameter()
 
     def requires(self):
diff --git a/metrik/tasks/ice.py b/metrik/tasks/ice.py
index 52a57cd..e80f967 100644
--- a/metrik/tasks/ice.py
+++ b/metrik/tasks/ice.py
@@ -1,3 +1,4 @@
+from __future__ import print_function
 from luigi.task import Task
 from luigi.parameter import DateParameter, Parameter
 # noinspection PyUnresolvedReferences
@@ -25,7 +26,8 @@ class LiborRateTask(Task):
     currency = Parameter()
 
     def output(self):
-        return MongoTarget('libor', hash(self.task_id))
+        h = hash(str(self.to_str_params()))
+        return MongoTarget('libor', h)
 
     def run(self):
         libor_record = self.retrieve_data(self.date, self.currency)