datastore.get() requires a list

See http://googlecloudplatform.github.io/gcloud-python/

The snippet is:

``` python
from gcloud import datastore
datastore.set_defaults()

product_key = datastore.Key('Product', 123)
print datastore.get([product_key])
```

I'd expect it to be:

``` python
from gcloud import datastore
product_key = datastore.Key('Product', 123)
product = datastore.get(product_key)
```
