add object factory

app/src/object_factory.py

@@ -0,0 +1,13 @@
+
+class ObjectFactory:
+    def __init__(self):
+        self._builders = {}
+
+    def register_builder(self, key, builder):
+        self._builders[key] = builder
+
+    def create(self, key, **kwargs):
+        builder = self._builders.get(key)
+        if not builder:
+            raise ValueError(key)
+        return builder(**kwargs)