Maybe merely a nitpick, but it sure is nice when the code, data and comments are consistent with themselves (and match the narrative exposition though that's not relevant in this case):

key1...
key1...
key43...
key1...
key2....

 - i believe the structure is clear:
 - there are two keys
 - ....
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Maybe you're using zero-based counting?

perl -E "my @keys = qw/1 2 43/; say $_ for( @keys); say \"count of \$#
+keys: $#keys\";"
1
2
43
count of $#keys: 2
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