use strict;
use Data::Dumper;

package First;

sub new { 
   my $class = shift;
   my $self  = {
      foo => 'bar'
   };
   return bless $self, $class;
}

sub test {
   my $self = shift;
   my $arg  = shift || 10;
   return ($arg > 9) ? "okay" : bless $self, 'Second';
}

package Second;

sub new { 
   my $class = shift;
   my $self  = {
      foo => 'qux'
   };
   return bless $self, $class;
}

sub test {
   my $self = shift;
   my $arg  = shift || 4;
   return ($arg > 5) ? "okay" : undef;
}

package main;

my $arg = shift || 10;
my $t   = First->new();

if (ref $t->test($arg)) {
   warn "first failed, trying second...";
   die "second failed" unless $t->test($arg);
}

print (ref $t, " passed\n");

print Dumper $t;