Initial commit. Basic models mostly done.

venv/lib/python3.8/site-packages/pip/_internal/distributions/installed.py

@@ -0,0 +1,24 @@
+from pip._internal.distributions.base import AbstractDistribution
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional
+
+    from pip._vendor.pkg_resources import Distribution
+    from pip._internal.index.package_finder import PackageFinder
+
+
+class InstalledDistribution(AbstractDistribution):
+    """Represents an installed package.
+
+    This does not need any preparation as the required information has already
+    been computed.
+    """
+
+    def get_pkg_resources_distribution(self):
+        # type: () -> Optional[Distribution]
+        return self.req.satisfied_by
+
+    def prepare_distribution_metadata(self, finder, build_isolation):
+        # type: (PackageFinder, bool) -> None
+        pass