【Python】PyAutoGuiインストールエラー対策（2020.08.09）

#概要
PyAutoGuiをインストールしようとしたらエラー発生。コメントを見ると、PyMsgBoxのインストールでエラーが出ていたため、バージョンを下げて個別にインストール。もう一度PyAutoGuiを試したらインストールできた。

#エラー内容と対策方法
4行目「pymsgbox」でエラーを出していることがわかる。とりあえずpymsgboxのバージョンを下げて試したところインストールできた。その状態だとPyAutoGuiを無事インストールできた。

```
C:\WINDOWS\system32>pip install PyAutoGUI
Collecting PyAutoGUI
  Using cached PyAutoGUI-0.9.50.tar.gz (57 kB)
Collecting pymsgbox
  Using cached PyMsgBox-1.0.8.tar.gz (18 kB)
  Installing build dependencies ... error
  ERROR: Command errored out with exit status 1:
   command: 'c:\users\username\anaconda3\python.exe' 'c:\users\username\anaconda3\lib\site-packages\pip' install --ignore-installed --no-user --prefix 'C:\Users\username\AppData\Local\Temp\pip-build-env-o7p6t8ru\overlay' --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- 'setuptools>=40.8.0' wheel
       cwd: None
  Complete output (42 lines):
  Traceback (most recent call last):
    File "c:\users\username\anaconda3\lib\runpy.py", line 193, in _run_module_as_main
      "__main__", mod_spec)
    File "c:\users\username\anaconda3\lib\runpy.py", line 85, in _run_code
      exec(code, run_globals)
    File "c:\users\username\anaconda3\lib\site-packages\pip\__main__.py", line 26, in <module>
      sys.exit(_main())
    File "c:\users\username\anaconda3\lib\site-packages\pip\_internal\cli\main.py", line 73, in main
      command = create_command(cmd_name, isolated=("--isolated" in cmd_args))
    File "c:\users\username\anaconda3\lib\site-packages\pip\_internal\commands\__init__.py", line 104, in create_command
      module = importlib.import_module(module_path)
    File "c:\users\username\anaconda3\lib\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 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 "c:\users\username\anaconda3\lib\site-packages\pip\_internal\commands\install.py", line 17, in <module>
      from pip._internal.cli.req_command import RequirementCommand, with_cleanup
    File "c:\users\username\anaconda3\lib\site-packages\pip\_internal\cli\req_command.py", line 16, in <module>
      from pip._internal.index.collector import LinkCollector
    File "c:\users\username\anaconda3\lib\site-packages\pip\_internal\index\collector.py", line 14, in <module>
      from pip._vendor import html5lib, requests
    File "c:\users\username\anaconda3\lib\site-packages\pip\_vendor\requests\__init__.py", line 125, in <module>
      from . import utils
    File "c:\users\username\anaconda3\lib\site-packages\pip\_vendor\requests\utils.py", line 25, in <module>
      from . import certs
    File "c:\users\username\anaconda3\lib\site-packages\pip\_vendor\requests\certs.py", line 15, in <module>
      from pip._vendor.certifi import where
    File "c:\users\username\anaconda3\lib\site-packages\pip\_vendor\certifi\__init__.py", line 1, in <module>
      from .core import contents, where
    File "c:\users\username\anaconda3\lib\site-packages\pip\_vendor\certifi\core.py", line 12, in <module>
      from importlib.resources import path as get_path, read_text
    File "c:\users\username\anaconda3\lib\importlib\resources.py", line 11, in <module>
      from typing import Iterable, Iterator, Optional, Set, Union   # noqa: F401
    File "c:\users\username\anaconda3\lib\site-packages\typing.py", line 1357, in <module>
      class Callable(extra=collections_abc.Callable, metaclass=CallableMeta):
    File "c:\users\username\anaconda3\lib\site-packages\typing.py", line 1005, in __new__
      self._abc_registry = extra._abc_registry
  AttributeError: type object 'Callable' has no attribute '_abc_registry'
  ----------------------------------------
ERROR: Command errored out with exit status 1: 'c:\users\username\anaconda3\python.exe' 'c:\users\username\anaconda3\lib\site-packages\pip' install --ignore-installed --no-user --prefix 'C:\Users\username\AppData\Local\Temp\pip-build-env-o7p6t8ru\overlay' --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- 'setuptools>=40.8.0' wheel Check the logs for full command output
```

#その他メモ
- conda, pip3でもやはりエラーを発生。