persistence for recurring api calls

backend/src/persistence.py

@@ -0,0 +1,18 @@
+from pymemcache.client.base import Client
+
+import constants
+
+
+class DummyClient:
+    _data = {}
+    def set(self, key, value, **kwargs):
+        self._data[key] = value
+
+    def get(self, key, **kwargs):
+        return self._data[key]
+
+
+if constants.MEMCACHE_HOST is None:
+    client = DummyClient()
+else:
+    client = Client(constants.MEMCACHE_HOST, timeout=1)