Not compatible with Python 3.10

[gaffney2010]

I'm getting an error on importing with Python version >=3.8. This is a bug because axelrod requires Python >=3.10, and these libraries are intended to be used together.

Error:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/multiprocessing/spawn.py", line 116, in spawn_main
    exitcode = _main(fd, parent_sentinel)
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/multiprocessing/spawn.py", line 126, in _main
    self = reduction.pickle.load(from_parent)
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/site-packages/axelrod_fortran/__init__.py", line 3, in <module>
    from .player import Player
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/site-packages/axelrod_fortran/player.py", line 25, in <module>
    manager.start()
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/multiprocessing/managers.py", line 579, in start
    self._process.start()
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/multiprocessing/process.py", line 121, in start
    self._popen = self._Popen(self)
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/multiprocessing/context.py", line 284, in _Popen
    return Popen(process_obj)
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/multiprocessing/popen_spawn_posix.py", line 32, in __init__
    super().__init__(process_obj)
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/multiprocessing/popen_fork.py", line 19, in __init__
    self._launch(process_obj)
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/multiprocessing/popen_spawn_posix.py", line 42, in _launch
    prep_data = spawn.get_preparation_data(process_obj._name)
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/multiprocessing/spawn.py", line 154, in get_preparation_data
    _check_not_importing_main()
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/multiprocessing/spawn.py", line 134, in _check_not_importing_main
    raise RuntimeError('''
RuntimeError: 
        An attempt has been made to start a new process before the
        current process has finished its bootstrapping phase.

        This probably means that you are not using fork to start your
        child processes and you have forgotten to use the proper idiom
        in the main module:

            if __name__ == '__main__':
                freeze_support()
                ...

        The "freeze_support()" line can be omitted if the program
        is not going to be frozen to produce an executable.
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/site-packages/axelrod_fortran/__init__.py", line 3, in <module>
    from .player import Player
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/site-packages/axelrod_fortran/player.py", line 25, in <module>
    manager.start()
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/multiprocessing/managers.py", line 583, in start
    self._address = reader.recv()
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/multiprocessing/connection.py", line 250, in recv
    buf = self._recv_bytes()
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/multiprocessing/connection.py", line 414, in _recv_bytes
    buf = self._recv(4)
  File "/usr/local/anaconda3/envs/my_axl/lib/python3.8/multiprocessing/connection.py", line 383, in _recv
    raise EOFError
EOFError

Steps to reproduce:

• conda create --name my_axl python=3.10
• conda activate my_axl
• pip install axelrod-fortran
• python
• import axelrod_fortran as axlf

[drvinceknight]

Eurgh...

[drvinceknight]

Eurgh...

That's unhelpful by me 😆. Will try and take a look!