diff --git a/demo_data/state_history_data.js b/demo_data/state_history_data.js
index 4d540ffe35..0f6f5f801b 100755
--- a/demo_data/state_history_data.js
+++ b/demo_data/state_history_data.js
@@ -1,5 +1,3 @@
-import objectAssign from 'object-assign';
-
 import stateData from './state_data';
 
 function getTime(minutesAgo) {
@@ -53,7 +51,7 @@ function addEntity(state, deltas) {
       } else if (!state.attributes) {
         attributes = change.attributes;
       } else {
-        attributes = objectAssign({}, state.attributes, change.attributes);
+        attributes = Object.assign({}, state.attributes, change.attributes);
       }
 
       const time = index === 0 ? getTime(maxTime) : getTime(maxTime - index * timeDiff +