anchor.diff:  handle_call({expect, FuncAri, Clauses}, _From, S) ->
       NewExpects = store_expect(S#state.mod, FuncAri,
                                 Clauses,
  -                              S#state.expects),
  -    {reply, ok, S#state{expects = NewExpects}};
  -handle_call({sequence, Func, Arity, Sequence}, _From, S) ->
  -    NewExpects = store_expect(S#state.mod, {Func, Arity},
  -                              [{arity_2_matcher(Arity), {sequence, Sequence}}],
  -                              S#state.expects),
  -    {reply, ok, S#state{expects = NewExpects}};
  -handle_call({loop, Func, Arity, Loop}, _From, S) ->
  -    NewExpects = store_expect(S#state.mod, {Func, Arity},
  -                              [{arity_2_matcher(Arity), {loop, Loop, Loop}}],
                                 S#state.expects),
       {reply, ok, S#state{expects = NewExpects}};
   handle_call({delete, Func, Arity}, _From, S) ->
  
positive.code: %% @see num_calls/3
  %% @see num_calls/4
  -spec history(Mod::atom(), Pid:: pid() | '_') -> history().
  history(Mod, Pid) when is_atom(Mod), is_pid(Pid) orelse Pid == '_' -> 
      match_history(match_mfa('_', Pid), call(Mod, history)).
  
  %% @spec unload() -> list(atom())
  
negative.code:                Arity::pos_integer(), Sequence::[term()]) -> ok.
  sequence(Mod, Func, Arity, Sequence)
    when is_atom(Mod), is_atom(Func), is_integer(Arity), Arity >= 0 ->
      Clause = {arity_2_matcher(Arity), ret_spec_2_answer(seq(Sequence))},
      call(Mod, {expect, {Func, Arity}, [Clause]});
  sequence(Mod, Func, Arity, Sequence) when is_list(Mod) ->
      lists:foreach(fun(M) -> sequence(M, Func, Arity, Sequence) end, Mod),
      ok.
  