test_map.py shows a warning

[amire80]

test_map.py shows a warning:

================================= test session starts =================================
platform linux -- Python 3.12.3, pytest-9.0.2, pluggy-1.6.0
rootdir: /home/amir/devel/python-mwxml
collected 4 items                                                                     

mwxml/map/tests/test_map.py ....                                                [100%]

================================== warnings summary ===================================
mwxml/map/tests/test_map.py::test_complex_error_handler
  /usr/lib/python3.12/multiprocessing/popen_fork.py:66: DeprecationWarning: This process (pid=1623998) is multi-threaded, use of fork() may lead to deadlocks in the child.
    self.pid = os.fork()

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
============================ 4 passed, 1 warning in 0.08s =============================

This probably comes from the para library. Since that library appears to have the same maintainer as mwxml, it can perhaps be fixed nicely there.

(As I was exploring this, I also noticed that the link from https://pypi.org/project/para/ to "Homepage" is broken.)

[halfak]

I dug into this a little bit yesterday. I was hoping that I could just blindly switch to using concurrent.futures.ProcessPoolExecutor but regretfully, it's important to have a "worker" iterate values rather than returning a single one. So I do think that it's worthwhile to keep the local implementation. I haven't gotten to the root of the issue yet.