It's a hash slice! Hash slices are wonderful things. Instead of accessing one key at a time, you can access a list of keys:

my %foo = (
    'one' => 1,
    'two' => 2,
    'three' => 3,
    'four' => 4,
);
print @foo{ 'one', 'two' }, "\n";
print @foo{ 'three', 'four' }, "\n";
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You can assign values to them too:

my %foo = ();

@foo{ 'one', 'two' } = (1, 2);
@foo{ 'three', 'four' } = (3, 4);

print keys %foo;
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