AssocArray to string is ok, but how to get the AssocArray from string? Thanks

[Frank Like]

Hi,everyone,
who can help me,about the "AssocArray to string is ok,but how to 
get the AssocArray from string? ".

For example:

SysTime[][string] AATimes;
AATimes["a1"] =[SysTime(DateTime(2017, 1, 1, 12, 33, 
33)),SysTime(DateTime(2017, 1, 2, 12, 33, 33))];
AATimes["a2"] =[SysTime(DateTime(2017, 1, 2, 12, 33, 
33)),SysTime(DateTime(2017, 1, 3, 12, 33, 33))];

   ubyte[] ua = cast(ubyte[])AATimes.to!string;
   writeln("ua is ",ua);
	
   string strTimes = cast(string)ua;
    writeln("strTimes is ",strTimes);

But now,how to get the AATimes from string?

Thanks.

Frank.