gh-120417: Fix "imported but unused" linter warnings (#120461)

Add __all__ to the following modules:
importlib.machinery, importlib.util and xml.sax.

Add also "# noqa: F401" in collections.abc,
subprocess and xml.sax.

* Sort __all__; remove collections.abc.__all__; remove private names

* Add tests

1 files changed, 10 insertions, 4 deletions

diff --git a/Lib/xml/sax/__init__.py b/Lib/xml/sax/__init__.py
index b657310..fe4582c 100644
--- a/Lib/xml/sax/__init__.py
+++ b/Lib/xml/sax/__init__.py
@@ -21,9 +21,9 @@ expatreader -- Driver that allows use of the Expat parser with SAX.
 
 from .xmlreader import InputSource
 from .handler import ContentHandler, ErrorHandler
-from ._exceptions import SAXException, SAXNotRecognizedException, \
-                        SAXParseException, SAXNotSupportedException, \
-                        SAXReaderNotAvailable
+from ._exceptions import (SAXException, SAXNotRecognizedException,
+                          SAXParseException, SAXNotSupportedException,
+                          SAXReaderNotAvailable)
 
 
 def parse(source, handler, errorHandler=ErrorHandler()):
@@ -55,7 +55,7 @@ default_parser_list = ["xml.sax.expatreader"]
 # tell modulefinder that importing sax potentially imports expatreader
 _false = 0
 if _false:
-    import xml.sax.expatreader
+    import xml.sax.expatreader    # noqa: F401
 
 import os, sys
 if not sys.flags.ignore_environment and "PY_SAX_PARSER" in os.environ:
@@ -92,3 +92,9 @@ def make_parser(parser_list=()):
 def _create_parser(parser_name):
     drv_module = __import__(parser_name,{},{},['create_parser'])
     return drv_module.create_parser()
+
+
+__all__ = ['ContentHandler', 'ErrorHandler', 'InputSource', 'SAXException',
+           'SAXNotRecognizedException', 'SAXNotSupportedException',
+           'SAXParseException', 'SAXReaderNotAvailable',
+           'default_parser_list', 'make_parser', 'parse', 'parseString']