@vaibhav The answer of @Saxtheowl is correct you need to add the resto of the expected parameters edit

def custom_serialize_value(value):
    return json.dumps(value, cls=CustomJSONEncoder).encode('UTF-8')

to

def custom_serialize_value(value, key, task_id, dag_id, run_id, map_index):
    return json.dumps(value, cls=CustomJSONEncoder).encode('UTF-8')