KERML — No textual syntax or derivation rules for isDirected

8.2.5.5 Connectors Concrete Syntax
8.3.4.5.1 Connectors Abstract Syntax - Overview
8.3.4.5.3 Connector - Attributes
The Connector Abstract Syntax and Attributes section both show a isDirected : Boolean attribute.
Neither show isDirected as a derived attribute, and there is no derivation constraint,
but there is also no textual notation to allow language users to set the attribute to true.
As far as I can tell, it will always be false, even though the description of the attribute states,
at least for binary connectors, there should be times where it could be true.