code: def Validate(self,
                 problems=None,
                 validate_children=True,
                 today=None,
                 service_gap_interval=None):
      
  
      if not problems:
        problems = self.problem_reporter
  
      self.ValidateAgenciesHaveSameAgencyTimezone(problems)
      self.ValidateFeedInfoLangMatchesAgencyLang(problems)
      self.ValidateServiceRangeAndExceptions(problems, today,
                                             service_gap_interval)
      # TODO: Check Trip fields against valid values
      self.ValidateStops(problems, validate_children)
      #TODO: check that every station is used.
      # Then uncomment testStationWithoutReference.
      self.ValidateNearbyStops(problems)
      self.ValidateRouteNames(problems, validate_children)
      self.ValidateTrips(problems)
      self.ValidateRouteAgencyId(problems)
      self.ValidateTripStopTimes(problems)
      self.ValidateUnusedShapes(problems)
docs: Validates various holistic aspects of the schedule
         (mostly interrelationships between the various data sets).