toJson method
Implementation
Map<String, Object?> toJson() => {
if (category != null) 'category': category,
if (column != null) 'column': column,
if (data != null) 'data': data,
if (group != null) 'group': group,
if (line != null) 'line': line,
if (locationReference != null) 'locationReference': locationReference,
'output': output,
if (source != null) 'source': source,
if (variablesReference != null)
'variablesReference': variablesReference,
};