If there is no information, the nullFlavor attribute shall have a value of 'NI' and
the "value" and "use" attributes shall be omitted, otherwise the nullFlavor attribute
shall not be present, and the "value" and "use" attributes shall be present.
Optionalities and Cardinalities of the following two items shall be interpreted according
to this rule: e.g. is not expected to have two nullFlavored telecom elements.
Healthcare Facility's Country. Mandatory for ClinicalDocument/author and ClinicalDocument/documentationOf/serviceEvent/performer,
required in other cases. When used addr.country it is always bound to the eHDSICountry
value set.