Implement custom argparse action for version display

Substituted the simple version argument with a custom argparse VersionAction in main.py, enhancing the version output information. This new VersionAction class fetches version information from the __about__ file, combining it with the Python version, and formats it appropriately for output.

src/pip_safe/argparse_version.py

@@ -0,0 +1,29 @@
+"""Provides a custom argparse action to show program's version and exit."""
+import logging
+import sys as _sys
+from argparse import SUPPRESS, Action
+
+from .__about__ import __version__
+
+
+log = logging.getLogger(__name__)
+
+
+class VersionAction(Action):
+    """Custom argparse action to show program's version and exit."""
+
+    def __init__(self, **kwargs):
+        # Set default values if not provided in kwargs
+        kwargs.setdefault("dest", SUPPRESS)
+        kwargs.setdefault("default", SUPPRESS)
+        kwargs.setdefault("nargs", 0)
+        kwargs.setdefault("help", "show program's version number and exit")
+        super().__init__(**kwargs)
+        self.version = kwargs.get("version2")
+
+    def __call__(self, parser, namespace, values, option_string=None):
+        version = f"%(prog)s {__version__}, Python {_sys.version_info.major}.{_sys.version_info.minor}"
+        formatter = parser.formatter_class(prog=parser.prog)
+        formatter.add_text(version)
+        _sys.stdout.write(formatter.format_help())
+        parser.exit()

src/pip_safe/main.py

@@ -9,7 +9,7 @@
 import six
 from tabulate import tabulate
 
-from pip_safe.__about__ import __version__
+from pip_safe.argparse_version import VersionAction
 from pip_safe.utils import (
     symlink,
     make_sure_path_exists,
@@ -361,11 +361,8 @@ def main():
     parser.add_argument(
         "--system", dest="system", action="store_true", help="Install for all users"
     )
-    parser.add_argument(
-        "--version",
-        action="version",
-        version="%(prog)s {version}".format(version=__version__),
-    )
+
+    parser.add_argument("--version", action=VersionAction)
     parser.set_defaults(verbose=False, verbose_more=False, system=False)
     args = parser.parse_args()