code: def deserialize_non_framed_values(stream, header, verifier=None):
      
      _LOGGER.debug("Starting non-framed body iv/tag deserialization")
      (data_iv, data_length) = unpack_values(">{}sQ".format(header.algorithm.iv_len), stream, verifier)
      return data_iv, data_length
docs: Deserializes the IV and body length from a non-framed stream.
  
      :param stream: Source data stream
      :type stream: io.BytesIO
      :param header: Deserialized header
      :type header: aws_encryption_sdk.structures.MessageHeader
      :param verifier: Signature verifier object (optional)
      :type verifier: aws_encryption_sdk.internal.crypto.Verifier
      :returns: IV and Data Length values for body
      :rtype: tuple of bytes and int