use strict;
use warnings;
use Math::BigInt;

# The following line of code will die with:
# Can't locate object method "palt" via package "Math::BigInt" at try.pl line 7.
# palt Math::BigInt->new(123456);

# But this next rendition is fine, and works as expected:
palt(Math::BigInt->new(123456));

sub palt {
  my $arg= shift;
  print "$arg\n";
}

__END__
Outputs:
123456