anchor.diff:  	CleanSpec = re:replace(TrimmedSpec, "[^A-Za-z]", "", [global, {return,list}]),
   	(CleanSpec =:= TrimmedSpec) and (length(CleanSpec) == 1).
   
  -diamond(Spec) -> 
  +diamond([Spec|_]) -> 
   	ValidSpec = is_valid_spec(Spec),
       if
       	ValidSpec ->
  
positive.code: positive_smoke_test() ->
      ?assert(diamond(['Z'])).
  
  negative_smoke_test() ->
      ?assertNot(diamond([';'])).
  
  -endif.
negative.code: 			io:format(user, "\nINVALID INPUT\n", []),
  			false
  	end.
  
  diamond() -> 
  	io:format(user, "\nINVALID INPUT\n", []),
  	false.	
  
  -ifdef(TEST).
  
  