--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/python3.8/site-packages/pip/_vendor/cachecontrol/cache.py	Mon Jul 27 03:47:31 2020 -0400
@@ -0,0 +1,39 @@
+"""
+The cache object API for implementing caches. The default is a thread
+safe in-memory dictionary.
+"""
+from threading import Lock
+
+
+class BaseCache(object):
+
+    def get(self, key):
+        raise NotImplementedError()
+
+    def set(self, key, value):
+        raise NotImplementedError()
+
+    def delete(self, key):
+        raise NotImplementedError()
+
+    def close(self):
+        pass
+
+
+class DictCache(BaseCache):
+
+    def __init__(self, init_dict=None):
+        self.lock = Lock()
+        self.data = init_dict or {}
+
+    def get(self, key):
+        return self.data.get(key, None)
+
+    def set(self, key, value):
+        with self.lock:
+            self.data.update({key: value})
+
+    def delete(self, key):
+        with self.lock:
+            if key in self.data:
+                self.data.pop(key)