@Override
        @Nullable
        public T get() {
            checkState(this.injector != null, "calling get() before setInjector()!");

            if (injector.getExistingBinding(key) == null) {
                return defaultValue;
            } else {
                return injector.getInstance(key);
            }
        }
Bind a different type as the given binding. This allows binding e.g. implementations to interface types.
guice/src/main/java/org/jdbi/v3/guice/internal/InternalLooseImportBindingBuilder.java