The `session` module has the following methods:
-### session.fromPartition(partition)
+### session.fromPartition(partition[, options])
* `partition` String
+* `options` Object
+ * `cache` Boolean - Whether to enable cache.
-Returns a new `Session` instance from `partition` string.
+Returns a `Session` instance from `partition` string. When there is an existing
+`Session` with the same `partition`, it will be returned; othewise a new
+`Session` instance will be created with `options`.
If `partition` starts with `persist:`, the page will use a persistent session
available to all pages in the app with the same `partition`. if there is no
`persist:` prefix, the page will use an in-memory session. If the `partition` is
empty then default session of the app will be returned.
+To create a `Session` with `options`, you have to ensure the `Session` with the
+`partition` has never been used before. There is no way to change the `options`
+of an existing `Session` object.
+
## Properties
The `session` module has the following properties: