title: Why does python unpack float act differently from 2.7.3 to 2.7.11
body: <p>I don't understand why the following code gives me different results on 2.7.3 vs 2.7.11 unfortunately I'm stuck in a production environment that is 2.7.3 at the moment.</p>
  
  <pre><code>import struct
  
  test = bytearray.fromhex("00804042")
  
  #I get an error
  #TypeError: unpack_from() argument 1 must be string or read-only buffer, not bytearray 
  #so I use buffer
  result = struct.unpack_from('f', buffer(test), 0)
  
  print result
  </code></pre>
  
  <p>In 2.7.11 I get 48.125, in 2.7.3 I get 1.1777e-38.  Also in 2.7.3 it would not accept a bytearray, hence the buffer(test) line.</p>