bindWithContext = function bindWithContext(decoratedStoryFn) {
    return function (update) {
      contextStore.value = Object.assign({}, contextStore.value, sanitizeStoryContextUpdate(update));
      return decoratedStoryFn(contextStore.value);
    };
  }
When you call the story function inside a decorator, e.g.:

```jsx
<div>{storyFn({ foo: 'bar' })}</div>
```

This will override the `foo` property on the `innerContext`, which gets
merged in with the default context