diff --git a/openquake/calculators/hazard/classical/core.py b/openquake/calculators/hazard/classical/core.py
index <HASH>..<HASH> 100644
--- a/openquake/calculators/hazard/classical/core.py
+++ b/openquake/calculators/hazard/classical/core.py
@@ -240,7 +240,6 @@ class ClassicalHazardCalculator(haz_general.BaseHazardCalculatorNext):
     #: The core calculation Celery task function, which accepts the arguments
     #: generated by :func:`task_arg_gen`.
     core_calc_task = hazard_curves
-    task_arg_gen = classical_task_arg_gen
 
     def initialize_hazard_curve_progress(self, lt_rlz):
         """
calcs/hazard/classical/core:

Missed one line.