🚀 go-pugleaf

X.521 uses the OBJECT-CLASS macro, an example is:

person OBJECT-CLASS
        SUBCLASS OF top
        MUST CONTAIN {
                commonName,
                surname}
        MAY CONTAIN {
                description,
                seeAlso,
                telephoneNumber,
                userPassword}
        ::= {objectClass 6}

Question: Is it possible, with this representation, to represent
DEFAULT attributes, i.e. attributes which need not be included
in the object, but which always must have a value, and where
a default value, defined somewhere (where??) is used if the
are not explicitly stored in the object.

If not: How should the notation be extended to be able to
handle DEFAULTed attributes?