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

def _extract_metadata(self, msg):
        header = msg['header']
        parent = msg['parent_header']
        msg_meta = msg['metadata']
        content = msg['content']
        md = {'msg_id' : parent['msg_id'],
              'received' : util.utcnow(),
              'engine_uuid' : msg_meta.get('engine', None),
              'follow' : msg_meta.get('follow', []),
              'after' : msg_meta.get('after', []),
              'status' : content['status'],
            }

        if md['engine_uuid'] is not None:
            md['engine_id'] = self._engines.get(md['engine_uuid'], None)

        if 'date' in parent:
            md['submitted'] = parent['date']
        if 'started' in msg_meta:
            md['started'] = util._parse_date(msg_meta['started'])
        if 'date' in header:
            md['completed'] = header['date']
        return md

def init_metadata(self, parent):
        """init metadata dict, for execute/apply_reply"""
        return {
            'started': utcnow(),
            'dependencies_met' : True,
            'engine' : self.ident,
        }

raw_msg = lost[msg_id].raw_msg
            idents, msg = self.session.feed_identities(raw_msg, copy=False)
            parent = self.session.unpack(msg[1].bytes)
            idents = [engine, idents[0]]

            # build fake error reply
            try:
                raise error.EngineError("Engine %r died while running task %r"%(engine, msg_id))
            except:
                content = error.wrap_exception()
            # build fake metadata
            md = dict(
                status=u'error',
                engine=engine.decode('ascii'),
                date=util.utcnow(),
            )
            msg = self.session.msg('apply_reply', content, parent=parent, metadata=md)
            raw_reply = list(map(zmq.Message, self.session.serialize(msg, ident=idents)))
            # and dispatch it
            self.dispatch_result(raw_reply)

        # finally scrub completed/failed lists
        self.completed.pop(engine)
        self.failed.pop(engine)

future = self._send(socket, "execute_request", content=content, ident=ident,
                            metadata=metadata)

        msg_id = future.msg_id
        self.outstanding.add(msg_id)
        if ident:
            # possibly routed to a specific engine
            if isinstance(ident, list):
                ident = ident[-1]
            if ident in self._engines.values():
                # save for later, in case of engine death
                self._outstanding_dict[ident].add(msg_id)
        self.history.append(msg_id)
        self.metadata[msg_id]['submitted'] = util.utcnow()

        return future