Assumes, that all definitions within next replace those within base (given the same name).
But if all definitions within next are maybe, then they are appended to the base definitions (updating them to be maybe from now on as well), similar to appendEnvironment.
Assumes, that all definitions within next replace those within base (given the same name). But if all definitions within next are maybe, then they are appended to the base definitions (updating them to be
maybefrom now on as well), similar to appendEnvironment.