Property code : WideString; (Read/Write)
The plain code symbol defined by the code system. if the code value is empty or null, then there is no code in the code system that represents the concept.
Code SHALL only contain characters that are either a letter, a digit, or one of '.', '-', '_' or ':'. Code systems that are used with CS SHALL NOT define code symbols or expression syntaxes that contain whitespace or any other characters not in this list.