fix usage for pinned versions

Signed-off-by: Zeke Sikelianos <[email protected]>

Author: zeke

README.md

@@ -97,12 +97,12 @@ You can cancel a running prediction:
 'canceled'
 ```
 
-By default, `model.predict()` uses the latest version. If you want to pin to a particular version, you can get a version with its ID:
+By default, `model.predict()` uses the latest version. If you want to pin to a particular version, you can get a version with its ID, then call the `predict()` method on that version:
 
 ```
 >>> model = replicate.models.get("replicate/hello-world")
 >>> version = model.versions.get("5c7d5dc6dd8bf75c1acaa8565735e7986bc5b66206b55cca93cb72c9bf15ccaa")
->>> model.predict(text="python")
+>>> version.predict(text="python")
 "hello python"
 ```