code: def image_aspect_ratio(self, image_index):
      img_annotations = self.annotations[
          self.id_to_image_id[image_index]
      ]
      height, width = img_annotations["h"], img_annotations["w"]
      return float(width) / float(height)
  
imports: import csv
  import json
  import os
  import warnings
  import numpy
  from PIL import Image
  from .generator import Generator
  from ..utils.image import read_image_bgr
label_desc: Use image node_id 9 for calling the OpenImagesGenerator obj's underlying member method code with example usage: obj.image_aspect_ratio(image_index) and returns: unknown