nullableMappedToString method Null safety
Implementation
static String? nullableMappedToString(Map<String, dynamic>? value) =>
value != null && value.containsKey('\$') ? mappedToString(value) : null;
static String? nullableMappedToString(Map<String, dynamic>? value) =>
value != null && value.containsKey('\$') ? mappedToString(value) : null;