code: def span_number_to_date(span: int) -> Tuple[int, int, int]:
      """Given a span number, convert it to the corresponding calendar date."""
      date = UNIX_EPOCH_DATE + datetime.timedelta(span)
      return date.year, date.month, date.day
  
imports: import datetime
  import os
  import re
  from typing import Any, Dict, Iterable, List, Optional, Tuple, Union
  from absl import logging
  import numpy
  from tfx.dsl.io import fileio
  from tfx.proto import example_gen_pb2
  from tfx.proto import range_config_pb2
  from tfx.utils import io_utils
  from google.protobuf import json_format
  from tensorflow.core.example import example_pb2
  from tensorflow.core.example import feature_pb2
label_desc: Use image node_id 8 for calling a global function with example usage: span_number_to_date(span) and returns: date,  date,  date