gistfile1.txt

#!/usr/bin/env python

"""A command-line utility called `parallel`."""

from concurrent.futures import ProcessPoolExecutor, wait
from os import chdir
from subprocess import check_call
from sys import argv

PACKAGES = [
    "contract_addresses",
    "contract_artifacts",
    "contract_wrappers",
    "json_schemas",
    "sra_client",
    "order_utils",
    "middlewares",
]

def run_cmd_on_package(package: str):
    """cd to the package dir, ./setup.py lint, cd .."""
    chdir(package)
    check_call(f"{' '.join(argv[1:])}".split())
    chdir("..")

wait(ProcessPoolExecutor().map(run_cmd_on_package, PACKAGES))




Calling that command-line utility:

$ ./parallel coverage run setup.py test
[...output showing that all executed processes completed without error...]
Traceback (most recent call last):
  File "./parallel", line 44, in <module>
    wait(ProcessPoolExecutor().map(run_cmd_on_package, PACKAGES))
  File "/home/gene/.pythonz/pythons/CPython-3.7.2/lib/python3.7/concurrent/futures/_base.py", line 284, in wait
    with _AcquireFutures(fs):
  File "/home/gene/.pythonz/pythons/CPython-3.7.2/lib/python3.7/concurrent/futures/_base.py", line 146, in __enter__
    future._condition.acquire()
AttributeError: 'NoneType' object has no attribute '_condition'