def __init__(self, number):
     self.threshold = number
     self.travel_data_attribute  = "travel_data.travel_time"
     self.zone_attribute_to_access = "wfrc.travel_zone.number_of_jobs"
     
     abstract_access_within_threshold_variable.__init__(self)
 def __init__(self, sector, threshold):
     self.threshold = threshold
     self.travel_data_attribute  = "travel_data.travel_time"
     self.zone_attribute_to_access = "wfrc.travel_zone.number_of_jobs_of_sector_" + str(sector)
     
     abstract_access_within_threshold_variable.__init__(self)