title: How to read pickle file?
body: <p>I created some data and stored it several times like this:</p>
  
  <pre><code>with open('filename', 'a') as f:
          pickle.dump(data, f)
  </code></pre>
  
  <p>Every time the size of file increased, but when I open file</p>
  
  <pre><code>with open('filename', 'rb') as f:
      x = pickle.load(f)
  </code></pre>
  
  <p>I can see only data from the last time. 
  How can I correctly read file?</p>