Primitive type 'cs'
Coded data in its simplest form, consists of a code. The code system and code system version is fixed by the context in which the value occurs. 'cs' is used for coded attributes that have a single HL7-defined value set.
A string which has at least one character and no leading or trailing whitespace and where there is no whitespace other than single spaces in the contents
All FHIR elements must have a @value or children
hasValue() or (children().count() > id.count())
cs attributes must not contain any whitespace
unique id for the element within a resource (for internal references)
Must have either extensions or value[x], not both