The create_from_upload() and create_from_data() methods now have

documentation covering their usage, and most of their parameters now

have default values.
One of the parameters has been replaced. The save parameter worked

differently than that on other similar methods. The implication is often

that by passing save=False, the objects will be created but not saved

to the database. In this case, however, we don't save anything to the

database, and the caller won't be able to save anything either, due to

the complexity of the objects created by these methods.
This parameter has been replaced with a validate_only parameter, which

better explains its purpose. When enabled, nothing is written to the

database and nothing is returned from the method.

Unit tests pass.