anchor.diff:  node_next_state(_State, NodeState, _Response, {call, ?MODULE, verify, []}) ->
       NodeState;
   node_next_state(_State, NodeState, _Response, {call, ?MODULE, read, [_Node, _Key]}) ->
  -    NodeState;
  -node_next_state(_State, NodeState, {error, not_primary}, {call, ?MODULE, write, [_Node, _Key, _Value]}) ->
       NodeState;
   node_next_state(_State, #node_state{store=Store0}=NodeState, _Response, {call, ?MODULE, write, [_Node, Key, Value]}) ->
       Store = dict:store(Key, Value, Store0),
  
positive.code: value() ->
      oneof([1, 2, 3]).
  
  node_name() ->
      oneof(names()).
  
  
negative.code: 
  %% What node-specific operations should be called.
  node_commands() ->
      [{call, ?MODULE, write, [primary_node_name(), key(), value()]},
       {call, ?MODULE, read, [primary_node_name(), key()]}].
  
  %% Assertion commands.
  node_assertion_functions() ->
  