use 5.014;

package Car {
    sub new { bless \@_, shift }
    sub go  { say "brmm!" }
}

package Spacecraft {
    sub new { bless \@_, shift }
    sub go  { say "whoosh!" }
}

my $vehicle = int(rand 2) ? Car->new : Spacecraft->new;

# Is $vehicle a car or a spacecraft?
# It doesn't matter!
$vehicle->go;
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