_format(sections){
        if(!sections.length){throw '[LT02] List without sections';}
        if(sections.length > 1 && sections.filter(s => typeof s.title == 'undefined').length > 1){throw '[LT05] You can\'t have more than one empty title.';}
        return sections.map( (section) =>{
            if(!section.rows.length){throw '[LT03] Section without rows';}
            return {
                title: section.title ? section.title : undefined,
                rows: section.rows.map( (row) => {
                    if(!row.title){throw '[LT04] Row without title';}
                    return {
                        rowId: row.id ? row.id : Util.generateHash(6),
                        title: row.title,
                        description: row.description ? row.description : ''
                    };
                })
            };
        });
    }
Creates section array from simple array
@param {Array<any>} sections
@returns {Array<any>}
@example
Input: [{title:'sectionTitle',rows:[{id:'customId', title:'ListItem2', description: 'desc'},{title:'ListItem2'}]}}]
Returns: [{'title':'sectionTitle','rows':[{'rowId':'customId','title':'ListItem1','description':'desc'},{'rowId':'oGSRoD','title':'ListItem2','description':''}]}]