Update dask to 0.15.0 will solve the issue

update cmd: conda update dask

input pip show dask will show follow message

Name: dask
Version: 0.15.0
Summary: Parallel PyData with Task Scheduling
Home-page: http://github.com/dask/dask/
Author: Matthew Rocklin
Author-email: mrocklin@gmail.com
License: BSD
Location: c:\anaconda3\lib\site-packages
Requires: