title: Pickle , read in data , unsupported pickle protocol: 3 python 2.7
body: <p>Beginner here, want to read in data with the file ending p.</p>
  
  <p>My code looks like this :</p>
  
  <pre><code>import pickle
  
  training_file = "/home/sk/CarND-Traffic-Sign-Classifier-Project/train.p"
  testing_file = "/home/sk/CarND-Traffic-Sign-Classifier-Project/test.p"
  with open(training_file, mode='rb') as f:
      train = pickle.load(f)
  with open(testing_file, mode='rb') as f:
      test = pickle.load(f)
  </code></pre>
  
  <p>I get the following error:</p>
  
  <p>ValueError: unsupported pickle protocol: 3</p>
  
  <p>Can someone point out how i can fix it, either changing protocol or reading in the data some other way ? </p>