Help! Help! 3

BLEAH!

       use Help 'Horrible::Thing';
        my $obj = Horrible::Thing->new(…);
        $obj->prev_sibling();

Now it says:

      Unknown method 'prev_sibling' called on object of class Horrible::Thing
      Perhaps try:
        DESTROY (via Horrible::Node)
        _ARRAY (via Horrible::Element)
        _CLASS (via Horrible::Node)
        _CODELIKE (via Horrible::Node)
        _INSTANCE (via Horrible::Statement)
        __LEXER__normal 
        __add_element (via Horrible::Node)
        __eq (via Horrible::Element)
        __equals (via Horrible::Element)
        __insert_after (via Horrible::Element)
        __insert_after_child (via Horrible::Node)
        __insert_before (via Horrible::Element)
        __insert_before_child (via Horrible::Node)
        __link_children (via Horrible::Node)
        __ne (via Horrible::Element)
        __nequals (via Horrible::Element)
        __position (via Horrible::Node)
        __replace_child (via Horrible::Node)
        _clear (via Horrible::Element)
        _complete 
        _ensure_location_present (via Horrible::Element)
        _error (via Horrible::Element)
        _flush_locations (via Horrible::Element)
        _wanted (via Horrible::Node)
        _xml_attr (via Horrible::Element)
        _xml_content (via Horrible::Element)
        _xml_name (via Horrible::Element)
        add_element (via Horrible::Node)
        ancestor_of (via Horrible::Element)
        child (via Horrible::Node)
        children (via Horrible::Node)
        class (via Horrible::Element)
        clone (via Horrible::Node)
        column_number (via Horrible::Element)
        contains (via Horrible::Node)
        content (via Horrible::Node)
        delete (via Horrible::Element)
        descendant_of (via Horrible::Element)
        document (via Horrible::Element)
        elements (via Horrible::Node)
        find (via Horrible::Node)
        find_any (via Horrible::Node)
        find_first (via Horrible::Node)
        first_element (via Horrible::Node)
        first_token (via Horrible::Element)
        insert_after (via Horrible::Statement)
        insert_before (via Horrible::Statement)
        label (via Horrible::Statement)
        last_element (via Horrible::Node)
        last_token (via Horrible::Element)
        line_number (via Horrible::Element)
        location (via Horrible::Node)
        logical_filename (via Horrible::Element)
        logical_line_number (via Horrible::Element)
        new (via Horrible::Statement)
        next_sibling (via Horrible::Element)
        next_token (via Horrible::Element)
        parent (via Horrible::Element)
       previous_sibling (via Horrible::Element)
        previous_token (via Horrible::Element)
        prune (via Horrible::Node)
        refaddr (via Horrible::Node)
        remove (via Horrible::Element)
        remove_child (via Horrible::Node)
        replace (via Horrible::Element)
        schild (via Horrible::Node)
        schildren (via Horrible::Node)
        scope 
        significant (via Horrible::Element)
        snext_sibling (via Horrible::Element)
        specialized (via Horrible::Statement)
        sprevious_sibling (via Horrible::Element)
        stable (via Horrible::Statement)
        statement (via Horrible::Element)
        tokens (via Horrible::Node)
        top (via Horrible::Element)
        visual_column_number (via Horrible::Element)