New Post: Not able to add sdtc:valueSet in Entity observation code.

Want to add the sdtc:valueSet in Entity.Observation.Code:

<code code="99201" codeSystem="2.16.840.1.113883.6.12" sdtc:valueSet="2.16.840.1.113883.3.464.1003.101.12.1001">

Thanks,
Shashwat