package TestClass;
use base qw(ConfClass);

sub new {
    my $class = shift;
    my $self = $class->SUPER::new(); # Initialize the superclass ConfClass here.
    ... # Do whatever you want.
    return $self;
}


##</code><code>##

package TestClass;
use ConfClass;

sub new {
    my $self = {};
    bless $self;
    $self->conf(ConfClass->new());
}

sub conf {
    my ($self, $conf) = @_;
    $self->{'_CONF'} = $conf if $conf;
    return $self->{'_CONF'};
}