Initial commit.

lib/python3.7/site-packages/pip/_internal/distributions/installed.py

@@ -0,0 +1,18 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from pip._internal.distributions.base import AbstractDistribution
+
+
+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):
+        return self.req.satisfied_by
+
+    def prepare_distribution_metadata(self, finder, build_isolation):
+        pass