Dependencies problem when using pipenv lock for 3.3.0

I have used the following Pipfile to generate Pipfile.lock:

[[Source]]
url = 'https://pypi.python.org/simple'
verify_ssl = true
name = 'pypi'

[requires]
python_version = '3.6'

[packages]
pytest = '*'
docker = '*'
#docker = '==3.2.1'

If not specifying the version for docker (Actually download 3.3.0), I met the following dependencies problem when executing "pipenv lock", but the command will be successful if i specify the docker's version is '3.2.1'.
I am using the latest version of pipenv ("11.10.1"), and host machine i am using is Mac OS Sierra (10.12.6)

$ pipenv lock
Locking [dev-packages] dependencies…
Locking [packages] dependencies…

Warning: Your dependencies could not be resolved. You likely have a mismatch in your sub-dependencies.
  You can use $ pipenv install --skip-lock to bypass this mechanism, then run $ pipenv graph to inspect the situation.Hint: try $ pipenv lock --pre if it is a pre-release dependency
Could not find a version that matches pypiwin32==219,==220
Tried: 219, 219, 219, 219, 219, 219, 219, 219, 219, 219, 219, 219, 219, 220, 220, 223, 223
There are incompatible versions in the resolved dependencies.

Reproduce the report from the shown Pipfile using Python 3.6 and docker 3.3.0, then inspect the generated Pipfile.lock and the pipenv lock output. Trace why the resolver requests incompatible pypiwin32 versions 219 and 220, compare the result with docker 3.2.1, and consider the issue done when the unpinned dependency set locks successfully or the incompatibility is clearly reported.