unable to run pipenv install

[tsbiberdorf]

when attempting to follow README and run the pipenv install
I received the following error:

~/projects/async-serial$ pipenv install
Traceback (most recent call last):
File "/usr/bin/pipenv", line 33, in
sys.exit(load_entry_point('pipenv==11.9.0', 'console_scripts', 'pipenv')())
File "/usr/lib/python3/dist-packages/pipenv/vendor/click/core.py", line 722, in call
return self.main(*args, **kwargs)
File "/usr/lib/python3/dist-packages/pipenv/vendor/click/core.py", line 697, in main
rv = self.invoke(ctx)
File "/usr/lib/python3/dist-packages/pipenv/vendor/click/core.py", line 1066, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "/usr/lib/python3/dist-packages/pipenv/vendor/click/core.py", line 895, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/usr/lib/python3/dist-packages/pipenv/vendor/click/core.py", line 535, in invoke
return callback(*args, **kwargs)
File "/usr/lib/python3/dist-packages/pipenv/cli.py", line 347, in install
from .import core
File "/usr/lib/python3/dist-packages/pipenv/core.py", line 21, in
import requests
File "/usr/lib/python3/dist-packages/pipenv/vendor/requests/init.py", line 65, in
from . import utils
File "/usr/lib/python3/dist-packages/pipenv/vendor/requests/utils.py", line 27, in
from .cookies import RequestsCookieJar, cookiejar_from_dict
File "/usr/lib/python3/dist-packages/pipenv/vendor/requests/cookies.py", line 172, in
class RequestsCookieJar(cookielib.CookieJar, collections.MutableMapping):
AttributeError: module 'collections' has no attribute 'MutableMapping'