@type t() :: %HL7v2.Segment.SCH{
  appointment_duration: term(),
  appointment_duration_units: term(),
  appointment_reason: term(),
  appointment_timing_quantity: term(),
  appointment_type: term(),
  entered_by_location: term(),
  entered_by_person: term(),
  entered_by_phone_number: term(),
  event_reason: term(),
  extra_fields: term(),
  filler_appointment_id: term(),
  filler_contact_address: term(),
  filler_contact_location: term(),
  filler_contact_person: term(),
  filler_contact_phone_number: term(),
  filler_order_number: term(),
  filler_status_code: term(),
  occurrence_number: term(),
  parent_filler_appointment_id: term(),
  parent_placer_appointment_id: term(),
  placer_appointment_id: term(),
  placer_contact_address: term(),
  placer_contact_location: term(),
  placer_contact_person: term(),
  placer_contact_phone_number: term(),
  placer_group_number: term(),
  placer_order_number: term(),
  schedule_id: term()
}