diff --git a/ppp_datamodel/nodes/list_operators.py b/ppp_datamodel/nodes/list_operators.py
index <HASH>..<HASH> 100644
--- a/ppp_datamodel/nodes/list_operators.py
+++ b/ppp_datamodel/nodes/list_operators.py
@@ -15,9 +15,9 @@ class ListNodeOperator(AbstractNode):
 
     def _check_attributes(self, attributes):
         super(ListNodeOperator, self)._check_attributes(attributes)
-        if not isinstance(attributes['list'], List):
+        if not isinstance(attributes['list'], (List, Sort)):
             raise TypeError('The “list” argument of the %s constructor '
-                            'should be a List node, not %r' %
+                            'should be a List or Sort node, not %r' %
                             (self.__class__.__name__, attributes['list']))
 
 class ListOperator(AbstractNode):
diff --git a/setup.py b/setup.py
index <HASH>..<HASH> 100755
--- a/setup.py
+++ b/setup.py
@@ -4,7 +4,7 @@ from setuptools import setup, find_packages
 
 setup(
     name='ppp_datamodel',
-    version='0.5.18',
+    version='0.5.19',
     description='Data model for the Projet Pensées Profondes.',
     url='https://github.com/ProjetPP/PPP-datamodel-Python',
     author='Valentin Lorentz',
Allow Sort nodes as child of ListNodeOperator too.