title: od_graph_def = tf.GraphDef() AttributeError: module 'tensorflow' has no attribute 'GraphDef'
body: <p>I have a mac and I am using tensorflow 2.0, python 3.7.
  I am following the tutorial for creating an object detection model for real-time application.
  but i am getting the following error:</p>
  <pre><code>&quot;Downloads/models/research/object_detection/object_detection_tutorial.py&quot;, line 43, in &lt;module&gt;
      od_graph_def = tf
    od_graph_def = tf.GraphDef()
  
  AttributeError: module 'tensorflow' has no attribute 'GraphDef'
  </code></pre>
  <p>below is the tutorial link:</p>
  <p>I checked the environment and I already have tensorflow environment in anaconda</p>
  <pre><code>import tensorflow as tf
  import zipfile
   
  from collections import defaultdict
  from io import StringIO
  from matplotlib import pyplot as plt
  from PIL import Image
   
  sys.path.append(&quot;..&quot;)
  from object_detection.utils import ops as utils_ops
  
  
  from utils import label_map_util
   
  from utils import visualization_utils as vis_util
  
  MODEL_NAME = 'ssd_mobilenet_v1_coco_2017_11_17'
  MODEL_FILE = MODEL_NAME + '.tar.gz'
  DOWNLOAD_BASE = 'http://download.tensorflow.org/models/object_detection/'
   
  PATH_TO_CKPT = MODEL_NAME + '/frozen_inference_graph.pb'
   
  PATH_TO_LABELS = os.path.join('data', 'mscoco_label_map.pbtxt')
   
  NUM_CLASSES = 90
  
  
  opener = urllib.request.URLopener()
  opener.retrieve(DOWNLOAD_BASE + MODEL_FILE, MODEL_FILE)
  tar_file = tarfile.open(MODEL_FILE)
  for file in tar_file.getmembers():
    file_name = os.path.basename(file.name)
    if 'frozen_inference_graph.pb' in file_name:
      tar_file.extract(file, os.getcwd())
   
  detection_graph = tf.Graph()
  with detection_graph.as_default():
    od_graph_def = tf.GraphDef()
    with tf.gfile.GFile(PATH_TO_CKPT, 'rb') as fid:
      serialized_graph = fid.read()
      od_graph_def.ParseFromString(serialized_graph)
      tf.import_graph_def(od_graph_def, name='')
  </code></pre>