code: def _get_crypto(keylen, hexkey, key):
      
      if keylen not in camcrypt.ACCEPTABLE_KEY_LENGTHS:
          raise ValueError("key length must be one of 128, 192, or 256")
  
      if hexkey:
          key = key.decode('hex')
  
      return camcrypt.CamCrypt(keylen=keylen, key=key)
docs: Return a camcrypt.CamCrypt object based on keylen, hexkey, and key.