Represents a possibly composite expression that may evaluate to true or false for a given change history item.
The intended use is querying the change groups of an issue to find those that contain a change item that matches
Allows us to perform operations over the clauses based on the passed in visitor. This method calls the
visit method on the visitor with this reference.
||the visitor to accept.
- the result of the visit operation who's type is specified by the incoming visitor.