Handling when results don't have a _type property set.
Handling when results don't have a _type property set.

The _type property will only be set in the HDS JSON if the record has
been saved in MongoDB. If it is created from an XML document, it won't
be there. In this case, we just assume PhysicalQuantity. In the
future, this should be enhanced to handle coded values.

intervention-engine/hdsfhir