code: public Tag addTag(String theScheme, String theTerm) {
  		Tag retVal = new Tag(theScheme, theTerm);
  		add(retVal);
  		myOrderedTags = null;
  		return retVal;
  	}
docs: Add a new tag instance
  
  @param theScheme
  The tag scheme (the system)
  @param theTerm
  The tag term (the code)
  @return Returns the newly created tag instance. Note that the tag is added to the list by this method, so you
  generally do not need to interact directly with the added tag.