Altering the three assignment lines to:

 my %chicago = map { $_ => 1 } qw(tiger bob munch toy);
 my %wisconsin = map { $_ => 1 } qw( tiger sara munch toy );
 my %rockford = map { $_ => 1 } qw( tiger sara love toy );
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gives you the following output:

 toy tiger
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The map command iterates over each element in the array (e.g. ('tiger','bob','munch','toy')) and assigns a key with the name of that element and a value of 1.