title: Append binary file to another binary file
body: <p>I want to append a previously-written binary file with a more recent binary file created.
  Essentially merging them. This is the sample code I am using:</p>
  
  <pre><code>with open("binary_file_1", "ab") as myfile:
      myfile.write("binary_file_2")
  </code></pre>
  
  <p>Except the error I get is <code>"TypeError: must be string or buffer, not file"</code></p>
  
  <p>But that's exactly what I am wanting to do! Add one binary file to the end of an earlier created binary file.</p>
  
  <p>I did try adding <code>"wb"</code> to the <code>"myfile.write("binary_file_2", "wb")</code>but it didn't like that. </p>