code: public boolean addValue(String property, String value) {
  		if (!has()) {
  			getOrCreate();
  		}
  		boolean added = false;
  		if (!hasValue(property, value)) {
  			TRow row = newRow();
  			row.setValue(COLUMN_PROPERTY, property);
  			row.setValue(COLUMN_VALUE, value);
  			getDao().insert(row);
  			added = true;
  		}
  		return added;
  	}
docs: Add a property value, creating the extension if needed
  
  @param property
  property name
  @param value
  value
  @return true if added, false if already existed