)

const (
	storageRESTVolume           = "vol"
	storageRESTVolumes          = "vols"
	storageRESTDirPath          = "dpath"
	storageRESTFilePath         = "fp"
	storageRESTVersionID        = "vid"
	storageRESTHealing          = "heal"
	storageRESTTotalVersions    = "tvers"
	storageRESTSrcVolume        = "svol"
	storageRESTSrcPath          = "spath"
	storageRESTDstVolume        = "dvol"
	storageRESTDstPath          = "dpath"

app = FastAPI()

data = {
    "isbn-9781529046137": "The Hitchhiker's Guide to the Galaxy",
    "imdb-tt0371724": "The Hitchhiker's Guide to the Galaxy",
    "isbn-9781439512982": "Isaac Asimov: The Complete Stories, Vol. 2",
}


def check_valid_id(id: str):
    if not id.startswith(("isbn-", "imdb-")):
        raise ValueError('Invalid ID format, it must start with "isbn-" or "imdb-"')
    return id


@app.get("/items/")

    while (values.hasNext()) {
      double value = values.next().doubleValue();
      count++;
      if (isFinite(value) && isFinite(mean)) {
        // Art of Computer Programming vol. 2, Knuth, 4.2.2, (15)
        mean += (value - mean) / count;
      } else {
        mean = calculateNewMeanNonFinite(mean, value);
      }
    }
    return mean;
  }

  /**

func (client *storageRESTClient) StatVol(ctx context.Context, volume string) (vol VolInfo, err error) {
	v, err := storageStatVolRPC.Call(ctx, client.gridConn, grid.NewMSSWith(map[string]string{
		storageRESTDiskID: *client.diskID.Load(),
		storageRESTVolume: volume,
	}))
	if err != nil {
		return vol, toStorageErr(err)
	}
	vol = *v
	// Performs shallow copy, so we can reuse.
	storageStatVolRPC.PutResponse(v)

    long count = 1;
    double mean = checkFinite(values[0]);
    for (int index = 1; index < values.length; ++index) {
      checkFinite(values[index]);
      count++;
      // Art of Computer Programming vol. 2, Knuth, 4.2.2, (15)
      mean += (values[index] - mean) / count;
    }
    return mean;
  }

  /**
   * Returns the <a href="http://en.wikipedia.org/wiki/Arithmetic_mean">arithmetic mean</a> of

	MakeVol(ctx context.Context, volume string) (err error)
	MakeVolBulk(ctx context.Context, volumes ...string) (err error)
	ListVols(ctx context.Context) (vols []VolInfo, err error)
	StatVol(ctx context.Context, volume string) (vol VolInfo, err error)
	DeleteVol(ctx context.Context, volume string, forceDelete bool) (err error)

	// WalkDir will walk a directory on disk and return a metacache stream on wr.

	if err := d.calcError(); err != nil {
		return nil, err
	}
	return d.disk.ListVols(ctx)
}

func (d *naughtyDisk) StatVol(ctx context.Context, volume string) (vol VolInfo, err error) {
	if err := d.calcError(); err != nil {
		return VolInfo{}, err
	}
	return d.disk.StatVol(ctx, volume)
}

  /** Adds the given pair of values to the dataset. */
  public void add(double x, double y) {
    // We extend the recursive expression for the one-variable case at Art of Computer Programming
    // vol. 2, Knuth, 4.2.2, (16) to the two-variable case. We have two value series x_i and y_i.
    // We define the arithmetic means X_n = 1/n \sum_{i=1}^n x_i, and Y_n = 1/n \sum_{i=1}^n y_i.

	}
	defer done(0, &err)

	return p.storage.ListVols(ctx)
}

func (p *xlStorageDiskIDCheck) StatVol(ctx context.Context, volume string) (vol VolInfo, err error) {
	ctx, done, err := p.TrackDiskHealth(ctx, storageMetricStatVol, volume)
	if err != nil {
		return vol, err
	}
	defer done(0, &err)

      max = value;
      if (!isFinite(value)) {
        sumOfSquaresOfDeltas = NaN;
      }
    } else {
      count++;
      if (isFinite(value) && isFinite(mean)) {
        // Art of Computer Programming vol. 2, Knuth, 4.2.2, (15) and (16)
        double delta = value - mean;
        mean += delta / count;
        sumOfSquaresOfDeltas += delta * (value - mean);
      } else {
        mean = calculateNewMeanNonFinite(mean, value);