@Override
  public boolean hasImportFromFuture(FutureFeature feature) {
    return withGreenStubOrAst(
      PyFileStub.class,
      stub -> stub.getFutureFeatures().get(feature.ordinal()),
      ast -> {
        Boolean enabled = myFutureFeatures.get(feature);
        if (enabled == null) {
          enabled = calculateImportFromFuture(feature);
          myFutureFeatures.put(feature, enabled);
          // NOTE: ^^^ not synchronized. if two threads will try to modify this, both can only be expected to set the same value.
        }
        return enabled;
      }
    );
  }
@Override
  public boolean hasImportFromFuture(FutureFeature feature)