`create_course` takes a json dict of field values ready for serialization (what you'd get back from `get_explicitly_set_fields_by_scope`); however, split wants native datetimes not the iso string format so that we can do date related functions in queries.

That said, this whole `for` loop could just be 
```
    fields = original.get_explicitly_set_fields_by_scope(Scope.content)
    fields.update(original.get_explicitly_set_fields_by_scope(Scope.settings))
```
and ignore that split wants datetimes in native format for now.