anchor.diff:  
   -spec header(atom() | binary(), #http_req{})
   	-> {binary() | undefined, #http_req{}}.
  -%% @equiv header(Name, Req) -> header(Name, Req, undefined)
  +%% @equiv header(Name, Req, undefined)
   header(Name, Req) ->
   	header(Name, Req, undefined).
   
  
positive.code: 
  -spec qs_val(binary(), #http_req{})
  	-> {binary() | true | undefined, #http_req{}}.
  %% @equiv qs_val(Name, Req) -> qs_val(Name, Req, undefined)
  qs_val(Name, Req) ->
  	qs_val(Name, Req, undefined).
  
  
negative.code: 	{Req#http_req.raw_qs, Req}.
  
  -spec binding(atom(), #http_req{}) -> {binary() | undefined, #http_req{}}.
  %% @equiv binding(Name, Req, undefined)
  binding(Name, Req) ->
  	binding(Name, Req, undefined).
  
  