{
   package MyClass;
   sub new  { my ($class) = @_;
              my $self = {};
              return $self; }
   sub test { print("Hi!"); }
}

my $o = MyClass->new();
$o->test();

##</code><code>##

Can't call method "test" on unblessed reference

##</code><code>##

{
   package MyClass;
   sub new  { my ($class) = @_;
              my $self = {};
              bless($self, $class);  # Added
              return $self; }
   sub test { print("Hi!"); }
}

my $o = MyClass->new();
$o->test();

##</code><code>##

Hi!