pipenv: Error when executing pipenv install

I’m getting an error when trying to run pipenv install

1. Ubuntu Linux
2. Python version: Python 3.6.4
3. Pipenv version: 11.1.5

Expected result

The dependencies install

Actual result

adler@masada:~/devel/project$ pipenv install 
Pipfile.lock not found, creating…
Locking [dev-packages] dependencies…
le "/home/adler/.local/lib/python3.6/site-packages/pipenv/resolver.py", line 19, in resolve
    return pipenv.utils.resolve_deps(packages, which, project=project, pre=pre, sources=sources, clear=clear, verbose=verbose)
  File "/home/adler/.local/lib/python3.6/site-packages/pipenv/../pipenv/utils.py", line 392, in resolve_deps
    resolved_tree, resolver = actually_resolve_reps(deps, index_lookup, markers_lookup, project, sources, verbose, clear, pre)
  File "/home/adler/.local/lib/python3.6/site-packages/pipenv/../pipenv/utils.py", line 325, in actually_resolve_reps
    resolved_tree.update(resolver.resolve(max_rounds=PIPENV_MAX_ROUNDS))
  File "/home/adler/.local/lib/python3.6/site-packages/pipenv/patched/piptools/resolver.py", line 102, in resolve
    has_changed, best_matches = self._resolve_one_round()
  File "/home/adler/.local/lib/python3.6/site-packages/pipenv/patched/piptools/resolver.py", line 200, in _resolve_one_round
    for dep in self._iter_dependencies(best_match):
  File "/home/adler/.local/lib/python3.6/site-packages/pipenv/patched/piptools/resolver.py", line 310, in _iter_dependencies
    yield InstallRequirement.from_line(dependency_string, constraint=ireq.constraint)
  File "/home/adler/.local/lib/python3.6/site-packages/pipenv/patched/pip/req/req_install.py", line 181, in from_line
    markers = Marker(markers)
  File "/home/adler/.local/lib/python3.6/site-packages/pipenv/patched/pip/_vendor/packaging/markers.py", line 282, in __init__
    raise InvalidMarker(err_str)
pip._vendor.packaging.markers.InvalidMarker: Invalid marker: 'python_version in "3.4, 3.5, 3.6"; python_version in "3.4, 3.5, 3.6"', parse error at '; python'