Parquet form:
message spark_schema {
  required int64 timeStamp;
  required binary providerId (UTF8);
  required binary origin (UTF8);
  required binary destination (UTF8);
  required binary departDate (UTF8);
  optional binary returnDate (UTF8);
  required binary cabinClass (UTF8);
  required int32 numOfAdults;
  required int32 numOfInfants;
  required int32 numOfChildren;
  optional binary fareClass (UTF8);
  required binary fareType (ENUM);
  required int32 baseFare;
  required int32 taxes;
  required int32 fees;
  required int32 discounts;
  required int32 totalFare;
  required binary currencyCode (UTF8);
  optional int32 totalFareForActualPassengers;
  required binary flightRefundType (UTF8);
  required int32 rating;
  required boolean isCached;
  required group onwardJourney (LIST) {
    repeated group array {
      required binary origin (UTF8);
      required binary destination (UTF8);
      required binary flightNumber (UTF8);
      optional int32 runsOn;
      required binary arrivalTime (UTF8);
      required binary departTime (UTF8);
      optional int32 arrivalOffset;
      optional int32 duration;
      required binary via (UTF8);
      optional int32 stops;
    }
  }
  optional group returnJourney (LIST) {
    repeated group array {
      required binary origin (UTF8);
      required binary destination (UTF8);
      required binary flightNumber (UTF8);
      optional int32 runsOn;
      required binary arrivalTime (UTF8);
      required binary departTime (UTF8);
      optional int32 arrivalOffset;
      optional int32 duration;
      required binary via (UTF8);
      optional int32 stops;
    }
  }
  required int32 advancePurchaseDays;
}