HazelcastSerializationError: <type 'collections.defaultdict'>

[arjunsingri]

When I set the in-memory-format to OBJECT, I get the below error. My value is basically a python dictionary:

2017-02-13 16:58:29,070 ERROR precal_consumer handle_message:162 8527 140214979946240 Got an exception while processing events <type 'collections.defaultdict'>
Traceback (most recent call last):
File "/opt/ns/bin/precal/precal_consumer.py", line 156, in handle_message
self.store_to_hazelcast_cache(query_obj, result)
File "/opt/ns/bin/precal/precal_consumer.py", line 228, in store_to_hazelcast_cache
hazelcast_report.put(mongo_id.key_to_hashid(group_key), values_dict)
File "/opt/ns/nsenv/local/lib/python2.7/site-packages/hazelcast/proxy/map.py", line 499, in put
value_data = self._to_data(value)
File "/opt/ns/nsenv/local/lib/python2.7/site-packages/hazelcast/serialization/base.py", line 76, in to_data
handle_exception(sys.exc_info()[1], sys.exc_info()[2])
File "/opt/ns/nsenv/local/lib/python2.7/site-packages/hazelcast/serialization/base.py", line 68, in to_data
serializer = self._registry.serializer_for(obj)
File "/opt/ns/nsenv/local/lib/python2.7/site-packages/hazelcast/serialization/base.py", line 205, in serializer_for
serializer = self.lookup_custom_serializer(obj_type)
File "/opt/ns/nsenv/local/lib/python2.7/site-packages/hazelcast/serialization/base.py", line 258, in lookup_custom_serializer
serializer = self.register_from_super_type(obj_type, super_type)
File "/opt/ns/nsenv/local/lib/python2.7/site-packages/hazelcast/serialization/base.py", line 300, in register_from_super_type
serializer = self._type_dict[super_type]
HazelcastSerializationError: <type 'collections.defaultdict'>