diff --git a/python/tamaas/dumpers/_helper.py b/python/tamaas/dumpers/_helper.py
index 89c8b51..3ee708e 100644
--- a/python/tamaas/dumpers/_helper.py
+++ b/python/tamaas/dumpers/_helper.py
@@ -1,104 +1,103 @@
 # @file
 # @section LICENSE
 #
 # Copyright (©) 2016-19 EPFL (École Polytechnique Fédérale de Lausanne),
 # Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as published
 # by the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU Affero General Public License for more details.
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 """
 Helper functions for dumpers
 """
 
 import numpy as np
 import os
 
 __all__ = ["PeriodicHelper", "step_dump", "directory_dump"]
 
 
 def makePeriodic(data):
     data = np.append(data, np.expand_dims(data[:, 0, ...], axis=1), axis=1)
     data = np.append(data, np.expand_dims(data[:, :, 0, ...], axis=2), axis=2)
     return data
 
 
 def makeTractionPeriodic(data):
     data = np.append(data, np.expand_dims(data[0, ...], axis=0), axis=0)
     data = np.append(data, np.expand_dims(data[:, 0, ...], axis=1), axis=1)
     return data
 
 
 class PeriodicHelper:
     """Helper class to make fields periodic"""
     def __getitem__(self, item):
         if item == 'traction':
             return makeTractionPeriodic
         else:
             return makePeriodic
 
 
 def step_dump(cls):
     """
     Decorator for dumper with counter for steps
     """
     orig_init = cls.__init__
     orig_dump = cls.dump
 
     def __init__(obj, *args, **kwargs):
         orig_init(obj, *args, **kwargs)
         obj.count = 0
 
     def postfix(obj):
         return "_{:04d}".format(obj.count)
 
     def dump(obj, *args, **kwargs):
         orig_dump(obj, *args, **kwargs)
         obj.count += 1
 
     cls.__init__ = __init__
     cls.dump = dump
     cls.postfix = property(postfix)
 
     return cls
 
 
 class directory_dump:
     """
     Decorator for dumper in a directory
     """
 
     def __init__(self,  directory=""):
         self.directory = directory
 
     def __call__(self, cls):
         directory = self.directory
-        orig_init = cls.__init__
+        orig_dump = cls.dump
         orig_filepath = cls.file_path.fget
 
-        def __init__(obj, *args, **kwargs):
-            orig_init(obj, *args, **kwargs)
-
+        def dump(obj, *args, **kwargs):
             if not os.path.exists(directory):
                 os.mkdir(directory)
-
             if not os.path.isdir(directory):
                 raise Exception('{} is not a directory'.format(directory))
 
+            orig_dump(obj, *args, **kwargs)
+
         def file_path(obj):
             return os.path.join(directory, orig_filepath(obj))
 
-        cls.__init__ = __init__
+        cls.dump = dump
         cls.file_path = property(file_path)
 
         return cls