$ pipenv install
Pipfile.lock (38f358) out of date, updating to (0177ba)…
Locking [dev-packages] dependencies…
✘ Locking Failed!
[pipenv.exceptions.ResolutionFailure]: File "/anaconda3/lib/python3.6/site-packages/pipenv/resolver.py", line 69, in resolve
[pipenv.exceptions.ResolutionFailure]: req_dir=requirements_dir
[pipenv.exceptions.ResolutionFailure]: File "/anaconda3/lib/python3.6/site-packages/pipenv/utils.py", line 726, in resolve_deps
[pipenv.exceptions.ResolutionFailure]: req_dir=req_dir,
[pipenv.exceptions.ResolutionFailure]: File "/anaconda3/lib/python3.6/site-packages/pipenv/utils.py", line 480, in actually_resolve_deps
[pipenv.exceptions.ResolutionFailure]: resolved_tree = resolver.resolve()
[pipenv.exceptions.ResolutionFailure]: File "/anaconda3/lib/python3.6/site-packages/pipenv/utils.py", line 395, in resolve
[pipenv.exceptions.ResolutionFailure]: raise ResolutionFailure(message=str(e))
[pipenv.exceptions.ResolutionFailure]: pipenv.exceptions.ResolutionFailure: ERROR: ERROR: Could not find a version that matches black
[pipenv.exceptions.ResolutionFailure]: Skipped pre-versions: 18.3a0, 18.3a0, 18.3a1, 18.3a1, 18.3a2, 18.3a2, 18.3a3, 18.3a3, 18.3a4, 18.3a4, 18.4a0, 18.4a0, 18.4a1, 18.4a1, 18.4a2, 18.4a2, 18.4a3, 18.4a3, 18.4a4, 18.4a4, 18.5b0, 18.5b0, 18.5b1, 18.5b1, 18.6b0, 18.6b0, 18.6b1, 18.6b1, 18.6b2, 18.6b2, 18.6b3, 18.6b3, 18.6b4, 18.6b4, 18.9b0, 18.9b0, 19.3b0, 19.3b0
[pipenv.exceptions.ResolutionFailure]: Warning: Your dependencies could not be resolved. You likely have a mismatch in your sub-dependencies.
First try clearing your dependency cache with $ pipenv lock --clear, then try the original command again.
Alternatively, 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.
ERROR: ERROR: Could not find a version that matches black
Skipped pre-versions: 18.3a0, 18.3a0, 18.3a1, 18.3a1, 18.3a2, 18.3a2, 18.3a3, 18.3a3, 18.3a4, 18.3a4, 18.4a0, 18.4a0, 18.4a1, 18.4a1, 18.4a2, 18.4a2, 18.4a3, 18.4a3, 18.4a4, 18.4a4, 18.5b0, 18.5b0, 18.5b1, 18.5b1, 18.6b0, 18.6b0, 18.6b1, 18.6b1, 18.6b2, 18.6b2, 18.6b3, 18.6b3, 18.6b4, 18.6b4, 18.9b0, 18.9b0, 19.3b0, 19.3b0
There are incompatible versions in the resolved dependencies.
[pipenv.exceptions.ResolutionFailure]: req_dir=requirements_dir
[pipenv.exceptions.ResolutionFailure]: File "/anaconda3/lib/python3.6/site-packages/pipenv/utils.py", line 726, in resolve_deps
[pipenv.exceptions.ResolutionFailure]: req_dir=req_dir,
[pipenv.exceptions.ResolutionFailure]: File "/anaconda3/lib/python3.6/site-packages/pipenv/utils.py", line 480, in actually_resolve_deps
[pipenv.exceptions.ResolutionFailure]: resolved_tree = resolver.resolve()
[pipenv.exceptions.ResolutionFailure]: File "/anaconda3/lib/python3.6/site-packages/pipenv/utils.py", line 395, in resolve
[pipenv.exceptions.ResolutionFailure]: raise ResolutionFailure(message=str(e))
[pipenv.exceptions.ResolutionFailure]: pipenv.exceptions.ResolutionFailure: ERROR: ERROR: Could not find a version that matches black
[pipenv.exceptions.ResolutionFailure]: Skipped pre-versions: 18.3a0, 18.3a0, 18.3a1, 18.3a1, 18.3a2, 18.3a2, 18.3a3, 18.3a3, 18.3a4, 18.3a4, 18.4a0, 18.4a0, 18.4a1, 18.4a1, 18.4a2, 18.4a2, 18.4a3, 18.4a3, 18.4a4, 18.4a4, 18.5b0, 18.5b0, 18.5b1, 18.5b1, 18.6b0, 18.6b0, 18.6b1, 18.6b1, 18.6b2, 18.6b2, 18.6b3, 18.6b3, 18.6b4, 18.6b4, 18.9b0, 18.9b0, 19.3b0, 19.3b0
[pipenv.exceptions.ResolutionFailure]: Warning: Your dependencies could not be resolved. You likely have a mismatch in your sub-dependencies.
First try clearing your dependency cache with $ pipenv lock --clear, then try the original command again.
Alternatively, 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.
ERROR: ERROR: Could not find a version that matches black
Skipped pre-versions: 18.3a0, 18.3a0, 18.3a1, 18.3a1, 18.3a2, 18.3a2, 18.3a3, 18.3a3, 18.3a4, 18.3a4, 18.4a0, 18.4a0, 18.4a1, 18.4a1, 18.4a2, 18.4a2, 18.4a3, 18.4a3, 18.4a4, 18.4a4, 18.5b0, 18.5b0, 18.5b1, 18.5b1, 18.6b0, 18.6b0, 18.6b1, 18.6b1, 18.6b2, 18.6b2, 18.6b3, 18.6b3, 18.6b4, 18.6b4, 18.9b0, 18.9b0, 19.3b0, 19.3b0
There are incompatible versions in the resolved dependencies.