title: Python fastest byte to string conversion
body: <p>I need to convert a byte array to a string to send to an SPI device.</p>
  
  <p>Is there a more efficient way of doing this ?</p>
  
  <pre><code>def writebytes(bytes):
    str = ""
    for i in bytes: str += chr(i)
    self.spi.transfer(str) 
  </code></pre>