Dependency issue with ptpython3

I think there is something up with the ptpython dependency in conda. This now depends on black, but does not seem to install it when the conda package is installed. If you install bliss using conda i.e:

cd bliss
conda install --file requirements-conda.txt
pip install --no-deps -e .

starting bliss (or daiquiri in my case) gives:

Traceback (most recent call last):
  File "/opt/conda/envs/daiquiri/bin/bliss", line 33, in <module>
    sys.exit(load_entry_point('bliss', 'console_scripts', 'bliss')())
  File "/opt/conda/envs/daiquiri/bin/bliss", line 25, in importlib_load_entry_point
    return next(matches).load()
  File "/opt/conda/envs/daiquiri/lib/python3.7/site-packages/importlib_metadata/__init__.py", line 166, in load
    module = import_module(match.group('module'))
  File "/opt/conda/envs/daiquiri/lib/python3.7/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 953, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 953, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/bliss/bliss/__init__.py", line 33, in <module>
    _patch_gevent()
  File "/bliss/bliss/common/greenlet_utils.py", line 122, in patch_gevent
    monkey.patch_all(thread=False)
  File "/opt/conda/envs/daiquiri/lib/python3.7/site-packages/gevent/monkey.py", line 1226, in patch_all
    from gevent import events
  File "/opt/conda/envs/daiquiri/lib/python3.7/site-packages/gevent/events.py", line 74, in <module>
    from pkg_resources import iter_entry_points
  File "/opt/conda/envs/daiquiri/lib/python3.7/site-packages/pkg_resources/__init__.py", line 3267, in <module>
    @_call_aside
  File "/opt/conda/envs/daiquiri/lib/python3.7/site-packages/pkg_resources/__init__.py", line 3251, in _call_aside
    f(*args, **kwargs)
  File "/opt/conda/envs/daiquiri/lib/python3.7/site-packages/pkg_resources/__init__.py", line 3280, in _initialize_master_working_set
    working_set = WorkingSet._build_master()
  File "/opt/conda/envs/daiquiri/lib/python3.7/site-packages/pkg_resources/__init__.py", line 582, in _build_master
    ws.require(__requires__)
  File "/opt/conda/envs/daiquiri/lib/python3.7/site-packages/pkg_resources/__init__.py", line 899, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/opt/conda/envs/daiquiri/lib/python3.7/site-packages/pkg_resources/__init__.py", line 785, in resolve
    raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'black' distribution was not found and is required by ptpython

If i install bliss without --no-deps things seem to play nice, but now black has been installed via pip and is the latest version i.e. 20, rather than the bliss dev requirement 19bxx:

pip install -e .

I have not yet dug into why black does not get installed with ptpython when installing via conda

Also, as an aside the ptpython dependency in setup.py has not been updated