toJson method
Implementation
Map<String, dynamic> toJson() => {
if (mode != null) 'mode': mode,
if (sources != null)
'sources': sources!.map((s) => s.toJson()).toList(),
if (maxSearchResults != null) 'max_search_results': maxSearchResults,
if (fromDate != null) 'from_date': fromDate,
if (toDate != null) 'to_date': toDate,
};