toJson method
Implementation
core.Map<core.String, core.dynamic> toJson() => {
if (frequentFlyerNumber != null)
'frequentFlyerNumber': frequentFlyerNumber!,
if (frequentFlyerProgramName != null)
'frequentFlyerProgramName': frequentFlyerProgramName!,
if (kind != null) 'kind': kind!,
};