title: Calculate CRC-CCITT (0xFFFF) for HEX string
body: <p>I'm trying to calulate CRC-CCITT (0xFFFF) for HEX string and get result back as HEX string. I tried <code>binascii</code> and <code>crc16</code> but I get int values and when I convert them to HEX it's not the value I expected. I need this:</p>
  
  <pre><code>hex_string = "AA01"
  crc_string = crccitt(hex_string)
  print("CRC: ", crc_string)
  
  &gt;&gt;&gt; CRC: FF9B
  </code></pre>