Problem with "import xarray"

Hi all, I have a problem with xarray, see below. Can anyone give any advice? Thanks.

psong@ollie0:~$ python
Python 3.6.5 |Intel Corporation| (default, Oct 12 2018, 19:28:48) 
[GCC 4.8.2 20140120 (Red Hat 4.8.2-15)] on linux
Type "help", "copyright", "credits" or "license" for more information.
Intel(R) Distribution for Python is brought to you by Intel Corporation.
Please check out: https://software.intel.com/en-us/python-distribution
>>> import xarray as xr
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/global/AWIsoft/intel/2019/intelpython3/lib/python3.6/site-packages/xarray/__init__.py", line 21, in <module>
    from .backends.api import (
  File "/global/AWIsoft/intel/2019/intelpython3/lib/python3.6/site-packages/xarray/backends/__init__.py", line 6, in <module>
    from .cfgrib_ import CfGribDataStore
  File "/global/AWIsoft/intel/2019/intelpython3/lib/python3.6/site-packages/xarray/backends/cfgrib_.py", line 7, in <module>
    from .locks import SerializableLock, ensure_lock
  File "/global/AWIsoft/intel/2019/intelpython3/lib/python3.6/site-packages/xarray/backends/locks.py", line 13, in <module>
    from dask.distributed import Lock as DistributedLock
  File "/global/AWIsoft/intel/2019/intelpython3/lib/python3.6/site-packages/dask/distributed.py", line 5, in <module>
    from distributed import *
  File "/global/AWIsoft/intel/2019/intelpython3/lib/python3.6/site-packages/distributed/__init__.py", line 5, in <module>
    from .actor import Actor, ActorFuture
  File "/global/AWIsoft/intel/2019/intelpython3/lib/python3.6/site-packages/distributed/actor.py", line 4, in <module>
    from .client import Future, default_client
  File "/global/AWIsoft/intel/2019/intelpython3/lib/python3.6/site-packages/distributed/client.py", line 44, in <module>
    from .batched import BatchedSend
  File "/global/AWIsoft/intel/2019/intelpython3/lib/python3.6/site-packages/distributed/batched.py", line 10, in <module>
    from .core import CommClosedError
  File "/global/AWIsoft/intel/2019/intelpython3/lib/python3.6/site-packages/distributed/core.py", line 20, in <module>
    from .comm import (connect, listen, CommClosedError,
  File "/global/AWIsoft/intel/2019/intelpython3/lib/python3.6/site-packages/distributed/comm/__init__.py", line 9, in <module>
    from .core import connect, listen, Comm, CommClosedError
  File "/global/AWIsoft/intel/2019/intelpython3/lib/python3.6/site-packages/distributed/comm/core.py", line 12, in <module>
    from ..utils import parse_timedelta
  File "/global/AWIsoft/intel/2019/intelpython3/lib/python3.6/site-packages/distributed/utils.py", line 1390, in <module>
    asyncio.set_event_loop_policy(tornado.platform.asyncio.AnyThreadEventLoopPolicy())
AttributeError: module 'tornado.platform.asyncio' has no attribute 'AnyThreadEventLoopPolicy'