9.3.4 Class Definition
A class is defined by a classdef element.  In addition to the component name attributes and specification document attributes, the following attributes are allowed:

•  conprop identifies the content property of the class, if any.

•  dsepprop identifies the data separator property of the class, if any. A class can have a data separator property only if it has a children property (i.e., a nodal content property).

•  mayadd identifies a category of classes that is used in the definition of the verification mapping in the transformation language. See section 11.4.1, Verification Mapping.  Only the value mayadd is allowed for this attribute. The attribute name can be omitted for this attribute.