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