This is the same line I (tried to) comment on earlier.  I think it should be `result.meta = None` and not `result.meta = OrderedDict()`.  The reason is that `OrderedDict()` as the container for `MetaData` is an implementation detail of the class.  So the `MetaData` API for "give me an empty MetaData object" is to set it to `None`.

Arguably this is a bit of a nit since the current code gives precisely the same result, but as an example for future code perhaps this should be fixed.