code: public void addStructureDefinition(StructureDefinition theStructureDefinition) {
  		Validate.notBlank(theStructureDefinition.getUrl(), "theStructureDefinition.getUrl() must not return a value");
  		myStructureDefinitions.put(theStructureDefinition.getUrl(), theStructureDefinition);
  	}
docs: Add a new StructureDefinition resource which will be available to the validator. Note that
  {@link StructureDefinition#getUrl() the URL field) in this resource must contain a value as this
  value will be used as the logical URL.