This function will add the provided Span object in the
Span Set object held internally by the Annotation/Span Set object.
The returned value of this function will always be a new Annotation
object with the provided Span object added.
Return Value:
This function returns a new Annotation object (of type CDM_Annotation)
with the provided span object added in the set of spans held by the
Annotation.
Notes:
This function is equivelant to CDM_AddAnnotationSpan/CDM_AddSpan (C++ API).