anchor.diff:  panel_configuration_model() ->
       #{
           %% The collection of user names associated with users properties.
  -        users => #{'_' => panel_configuration_users_model()}
  +        users => #{ '_' => panel_configuration_users_model()}
       }.
   
   -spec panel_configuration_users_model() -> maps:map().
  
positive.code:         %% The detailed error description.
          description => string,
          %% The name of a module containing function that returned error.
          module => {string, optional},
          %% The name of a function that returned error.
          function => {string, optional},
          %% The collection of hosts with associated error description.
          hosts => {#{'_' => error_model()}, optional}
      }.
  
  %%--------------------------------------------------------------------
  
negative.code: provider_configuration_model() ->
      #{
          cluster => provider_cluster_configuration_model(),
          oneprovider => { provider_configuration_oneprovider_model(), optional },
          onezone => { provider_configuration_onezone_model(), optional },
          onepanel => { panel_configuration_model(), optional }
      }.
  
  %%--------------------------------------------------------------------
  