How to use the ipyparallel.util.ensure_timezone function in ipyparallel

def init_record(msg):
    """Initialize a TaskRecord based on a request."""
    header = msg['header']
    return {
        'msg_id' : header['msg_id'],
        'header' : header,
        'content': msg['content'],
        'metadata': msg['metadata'],
        'buffers': msg['buffers'],
        'submitted': util.ensure_timezone(header['date']),
        'client_uuid' : None,
        'engine_uuid' : None,
        'started': None,
        'completed': None,
        'resubmitted': None,
        'received': None,
        'result_header' : None,
        'result_metadata': None,
        'result_content' : None,
        'result_buffers' : None,
        'queue' : None,
        'execute_input' : None,
        'execute_result': None,
        'error': None,
        'stdout': '',
        'stderr': '',

outstanding = self.queues[eid]

        for msg_id in outstanding:
            self.pending.remove(msg_id)
            self.all_completed.add(msg_id)
            try:
                raise error.EngineError("Engine %r died while running task %r" % (eid, msg_id))
            except:
                content = error.wrap_exception()
            # build a fake header:
            header = {}
            header['engine'] = uuid
            header['date'] = util.utcnow()
            rec = dict(result_content=content, result_header=header, result_buffers=[])
            rec['completed'] = util.ensure_timezone(header['date'])
            rec['engine_uuid'] = uuid
            try:
                self.db.update_record(msg_id, rec)
            except Exception:
                self.log.error("DB Error handling stranded msg %r", msg_id, exc_info=True)

def _add_tz(obj):
    if isinstance(obj, datetime):
        obj = ensure_timezone(obj)
    return obj

def _convert_timestamp(s):
    """Adapt text timestamp to datetime"""
    return ensure_timezone(dateutil_parse(s))