anchor.diff:  	{_,  {struct, VFObj}} = lists:keyfind("validFor", 1, Price),
   	{_, SDT} = lists:keyfind("startDateTime", 1, VFObj),
   	{_, EDT} = lists:keyfind("endDateTime", 1, VFObj),
  -	{ocs_rest:timestamp(SDT), ocs_rest:timestamp(EDT)};
  +	{ocs_rest:iso8601(SDT), ocs_rest:iso8601(EDT)};
   prod_price_vf(json, Price) ->
   	{SDateTime, EDateTime} = Price#price.valid_for,
   	SDT = {"startDateTime", ocs_rest:iso8601(SDateTime)},
  
positive.code: 	{_, {struct, VFObj}} = lists:keyfind("validFor", 1, Product),
  	{_, SDT} = lists:keyfind("startDateTime", 1, VFObj),
  	{_, EDT} = lists:keyfind("endDateTime", 1, VFObj),
  	{ocs_rest:timestamp(SDT), ocs_rest:timestamp(EDT)};
  prod_vf(json, Product) ->
  	case Product#product.valid_for of
  		{SDateTime, undefined} ->
  
negative.code: 		IsBundle = prod_isBundle(erlang_term, Object),
  		Status = prod_status(erlang_term, Object),
  		ValidFor = prod_vf(erlang_term, Object),
  erlang:display({?MODULE, ?LINE, ValidFor}),
  		Descirption = prod_description(erlang_term, Object),
  		case prod_offering_price(erlang_term, Object) of
  			{error, StatusCode} ->
  