If Storable worked with multi-dimensional hashes this code
would be of little value. Storable doesn't allow it,
or at least it didn't want to do it for me and no one on
here responded with a suggestion on how to get it to work.
See "Storable.pm: Storing Multi-dimensional Hashes How?"
Even Datadumper had a bug in it which made the storing
of multidimensional hashes a problem;
$Datadumper::quotekeys=1 is ignored after the first
dimension of the hash. Fortunately, DumperX works properly
but obviously this is only available on platforms with
XS extensions to Datadumper. Hopefully, the author of
Datadumper will find the glitch in short order.