For creating a CDA document -- you should not worry about these
attrubutes. Per the CDA schema (which is valuable to consult) -- these
attributes (classCode, moodCode) are optional on the XML instance. And
if present shall be set to default values depending on the element type
they are attributes for. These attributes essentially help trace back
elements of the CDA to elements of the RIM. So there is no clinical
significance in setting them and when not present -- they are just
assumed to be the default values declared in the schema.

For creating a CDA document -- you should not worry about these
attrubutes. Per the CDA schema (which is valuable to consult) -- these
attributes (classCode, moodCode) are optional on the XML instance. And
if present shall be set to default values depending on the element type
they are attributes for. These attributes essentially help trace back
elements of the CDA to elements of the RIM. So there is no clinical
significance in setting them and when not present -- they are just
assumed to be the default values declared in the schema.