anchor.diff:  -spec ipdr_codec(Event) -> IPDR
   	when
   		Event :: tuple(),
  -		IPDR :: #ipdr_wlan{} | #ipdr_voip{}.
  +		IPDR :: #ipdr_wlan{} | #ipdr_voip{} | undefined.
   %% @doc Convert `ocs_acct' log entry to IPDR log entry.
   %% @private
   ipdr_codec(Event) when size(Event) > 6,
  
positive.code: ipdr_log3(IpdrLog, _Start, End, SeqNum, {_Cont, [H | _]})
  		when element(1, H) > End ->
  	ipdr_log4(IpdrLog, SeqNum);
  ipdr_log3(IpdrLog, _Start, End, SeqNum, {Cont, [H | T]})
  		when element(6, H) == stop ->
  	case ipdr_codec(H) of
  		#ipdr_wlan{} = IPDR ->
  			NewSeqNum = SeqNum + 1,
  			case disk_log:log(IpdrLog, IPDR#ipdr_wlan{seqNum = NewSeqNum}) of
  				ok ->
  					ipdr_log3(IpdrLog, _Start, End, NewSeqNum, {Cont, T});
  				{error, Reason} ->
  					Descr = lists:flatten(disk_log:format_error(Reason)),
  					Trunc = lists:sublist(Descr, length(Descr) - 1),
  
negative.code: 							{log, IpdrLog}, {error, Reason}]),
  					disk_log:close(IpdrLog),
  					{error, Reason}
  			end;
  		_ ->
  			ipdr_log3(IpdrLog, Start, End, SeqNum, {Cont, T})
  			
  	end;
  ipdr_log3(IpdrLog, Start, End, SeqNum, {Cont, [_ | T]}) ->
  	ipdr_log3(IpdrLog, Start, End, SeqNum, {Cont, T}).
  