added pg_setting_export_example_enhanced.py and new method list_vpgs_from_exported_settings in vpgs.py

venv/lib/python3.9/site-packages/pip/_internal/models/index.py

@@ -0,0 +1,32 @@
+import urllib.parse
+
+
+class PackageIndex:
+    """Represents a Package Index and provides easier access to endpoints
+    """
+
+    __slots__ = ['url', 'netloc', 'simple_url', 'pypi_url',
+                 'file_storage_domain']
+
+    def __init__(self, url: str, file_storage_domain: str) -> None:
+        super().__init__()
+        self.url = url
+        self.netloc = urllib.parse.urlsplit(url).netloc
+        self.simple_url = self._url_for_path('simple')
+        self.pypi_url = self._url_for_path('pypi')
+
+        # This is part of a temporary hack used to block installs of PyPI
+        # packages which depend on external urls only necessary until PyPI can
+        # block such packages themselves
+        self.file_storage_domain = file_storage_domain
+
+    def _url_for_path(self, path: str) -> str:
+        return urllib.parse.urljoin(self.url, path)
+
+
+PyPI = PackageIndex(
+    'https://pypi.org/', file_storage_domain='files.pythonhosted.org'
+)
+TestPyPI = PackageIndex(
+    'https://test.pypi.org/', file_storage_domain='test-files.pythonhosted.org'
+)