diff --git a/pymisp/mispevent.py b/pymisp/mispevent.py
index 71dece1..be330ce 100644
--- a/pymisp/mispevent.py
+++ b/pymisp/mispevent.py
@@ -78,6 +78,7 @@ def _datetime_to_timestamp(d):
 class MISPAttribute(AbstractMISP):
 
     def __init__(self, describe_types=None):
+        super(MISPAttribute, self).__init__()
         if not describe_types:
             ressources_path = os.path.join(os.path.abspath(os.path.dirname(__file__)), 'data')
             with open(os.path.join(ressources_path, 'describeTypes.json'), 'r') as f:
@@ -284,6 +285,7 @@ class MISPAttribute(AbstractMISP):
 class MISPEvent(AbstractMISP):
 
     def __init__(self, describe_types=None, strict_validation=False):
+        super(MISPEvent, self).__init__()
         ressources_path = os.path.join(os.path.abspath(os.path.dirname(__file__)), 'data')
         if strict_validation:
             with open(os.path.join(ressources_path, 'schema.json'), 'r') as f: