title: Difference between calculation of from_bytes vs. unpack
body: <p>I've been trying to figure out why this byte array leads to different results using two approaches:</p>
  <pre class="lang-py prettyprint-override"><code>print(msg[16:20])
  &gt;&gt;&gt; b'\xe4\x86\xaaU'
  msg[16:20].hex()
  &gt;&gt;&gt; e486aa55
  print(int.from_bytes(msg[16:20], byteorder='big', signed='False'))
  &gt;&gt;&gt; -460936619
  print(unpack_from('!I', msg, offset=16)[0])
  &gt;&gt;&gt; 3834030677
  print(unpack('!I', msg[16:20])[0])
  &gt;&gt;&gt; 3834030677
  </code></pre>
  <p>How is it, that using the builtin <code>from_bytes()</code> function is calculating a wrong result? I've recalculated it on my own (<a href="https://stackoverflow.com/a/50509434">https://stackoverflow.com/a/50509434</a>) and the result should be similar to the one using <code>unpack()</code></p>
  <pre><code>228*256^3+134*256^2+170*256^1+85+256^0 = 3834030677
  </code></pre>
  <p>Hope to find my fault / wrong thinking with your guys help - thanks a lot in advance!</p>