liquibase-core/src/main/java/liquibase/Scope.java
public static void child(LiquibaseListener listener, ScopedRunner runner) throws Exception {
        child(listener, null, runner);
    }
public static void child(LiquibaseListener listener, ScopedRunner runner) throws Exception {
        child(listener, null, runner);
    }
Creates a new child scope that includes the given {@link LiquibaseListener}.
You cannot unassign a listener, they simply fall out of scope when the Scope does.

@see #getListeners(Class)