anchor.diff:  		ProdValidity = validity_period(ProdSTime, ProdETime),
   		if
   			ProdValidity =/= {error, format_error} ->
  -				ProdPriceType = price_type(ProdPriceTypeS),
   				{ProdUnits, ProdSize} = product_unit_of_measure(ProdUOMesasure),
   				Size = product_size(ProdUnits, octets, ProdSize),
   				RCPeriod = recurring_charge_period(RCPeriodS),
  
positive.code: 			{error, 400}
  	end.
  
  -spec validity_period(StartTime, EndTime) -> Result
  	when
  		StartTime	:: string(),
  
negative.code: find_status("pending_terminate") -> pending_terminate.
  
  -spec price_type(StringPriceType) -> PriceType when
  	StringPriceType :: string() | atom(),
  	PriceType		 :: recurring | one_time | usage | string().
  %% @private
  price_type("usage") -> usage;
  price_type("recurring") -> recurring;
  price_type("one_time") -> one_time;
  price_type(usage) -> "usage";
  price_type(recurring) -> "recurring";
  price_type(one_time) -> "one_time".
  
  