code: public static SourceSnippet callParentGetter(final Key<?> key,
        final GinjectorBindings parentBindings) {
      return new SourceSnippet() {
        public String getSource(InjectorWriteContext writeContext) {
          return writeContext.callParentGetter(key, parentBindings);
        }
      };
    }
docs: Creates a snippet that evaluates to an injected instance of the given key,
  as produced by the given parent injector.