It allows 

my $rv = $args{'Post'} ? $args{'Post'}->() : 1;

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to be simplified to 
my $rv = $args{'Post'}->();

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Or if the return value isn't checked, it allows 

$args{'Post'} and $args{'Post'}->();

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to be simplified to 
$args{'Post'}->();

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(sub{} would have been sufficient in the latter case.)

In reply to Re^3: what is sub {1;} by ikegami
in thread what is sub {1;} by mlgvalt

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