anchor.diff:  get_supported_groups(#supported_groups{supported_groups = Groups}) ->
       {ok, Groups}.
   
  +get_key_shares(undefined) ->
  +    [];
   get_key_shares(#key_share_client_hello{client_shares = ClientShares}) ->
       ClientShares;
   get_key_shares(#key_share_server_hello{server_share = ServerShare}) ->
  
positive.code: 
  get_signature_scheme_list(undefined) ->
      undefined;
  get_signature_scheme_list(#signature_algorithms_cert{
                          signature_scheme_list = ClientSignatureSchemes}) ->
      ClientSignatureSchemes;
  
negative.code:             true
      end.
  
  do_check_cert_sign_algo(_, _, undefined) ->
      {error, ?ALERT_REC(?FATAL, ?INSUFFICIENT_SECURITY, no_suitable_signature_algorithm)};
  do_check_cert_sign_algo(_, _, []) ->
      {error, ?ALERT_REC(?FATAL, ?INSUFFICIENT_SECURITY, no_suitable_signature_algorithm)};
  do_check_cert_sign_algo(SignAlgo, SignHash, [Scheme|T]) ->
  