code: def deserialize_header_auth(stream, algorithm, verifier=None):
      
      _LOGGER.debug("Starting header auth deserialization")
      format_string = ">{iv_len}s{tag_len}s".format(iv_len=algorithm.iv_len, tag_len=algorithm.tag_len)
      return MessageHeaderAuthentication(*unpack_values(format_string, stream, verifier))
docs: Deserializes a MessageHeaderAuthentication object from a source stream.
  
      :param stream: Source data stream
      :type stream: io.BytesIO
      :param algorithm: The AlgorithmSuite object type contained in the header
      :type algorith: aws_encryption_sdk.identifiers.AlgorithmSuite
      :param verifier: Signature verifier object (optional)
      :type verifier: aws_encryption_sdk.internal.crypto.Verifier
      :returns: Deserialized MessageHeaderAuthentication object
      :rtype: aws_encryption_sdk.internal.structures.MessageHeaderAuthentication