toJson method
Implementation
core.Map<core.String, core.dynamic> toJson() => {
if (endDate != null) 'endDate': endDate!,
if (label != null) 'label': label!,
if (returnDays != null) 'returnDays': returnDays!,
if (returnUntilDate != null) 'returnUntilDate': returnUntilDate!,
if (startDate != null) 'startDate': startDate!,
};