The structure of your input data also seems pretty hosed to me, but I could be missing something... shouldn't it be something closer to:

my $data = [
    mykey1 => { 'firstkey' => 'firstvalue', 'secondkey' => 'secondval'
+ },
    mykey2 => { 'ninza'    => 'turtle',     'Hurricane' => 'Dennis' },
+   
    mykey3 => [ [ 'one', 'two', 'three' ] ],                          
    mykey4 => [ [ 4, 5, 'three' ], [ 6, 7, 'four' ], [ 8, 9, 'five' ] 
+],
];
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