A copy constructor for builder of list/container yang statements

Builder which is generated for list and container yang statements should contain a copy constructor where parameter is type of build() method.
Example:

public class GroupBuilder {

public GroupBuilder(Group group) {
if (group instanceof GroupImpl)

{ GroupImpl groupImpl = (GroupImpl) group; // copy attributes here }

}

public Group build()

{ return new GroupImpl(this); }

}