package My::Module;

sub new {
    my $class = shift;
    my $self = {};    # no clutter!

    bless $self, $class;
}

sub some_method {
    my $self = shift;

    # we use it here
    my $result = $self->_csv->some_csv_action( @input ); # uses accessor
}

sub _csv {
    my $self = shift;

    # allow to be set from outside
    if(@_) {
        $self->{_csv} = shift;
    }

    # default to Text::CSV
    if( !defined $self->{_csv} ) {
        require Text::CSV;
        $self->{_csv} = Text::CSV->new( 'some args' );
    }

    return $self->{_csv};
}