diff --git a/api/change_set.py b/api/change_set.py
index 7e91608..fbcd489 100644
--- a/api/change_set.py
+++ b/api/change_set.py
@@ -1,12 +1,22 @@
 class ChangeSet:
-    def __init__(self) -> None:
+    def __init__(self):
         self.operations : list[dict[str, str]] = []
 
-    def add(self, type: str, id: str) -> None:
+    def add(self, type: str, id: str):
         self.operations.append({ 'operation': 'add', 'type': type, 'id': id })
+        return self
 
-    def delete(self, type: str, id: str) -> None:
+    def delete(self, type: str, id: str):
         self.operations.append({ 'operation': 'delete', 'type': type, 'id': id })
+        return self
 
-    def update(self, type: str, id: str, property: str) -> None:
-        self.operations.append({ 'operation': 'update', 'type': type, 'id': id, 'property': property })
\ No newline at end of file
+    def update(self, type: str, id: str, properties: list[str]):
+        self.operations.append({ 'operation': 'update', 'type': type, 'id': id, 'properties': properties })
+        return self
+
+    def append(self, other) -> None:
+        self.operations += other.operations
+        return self
+
+    def compress(self) -> None:
+        return self