code: def epoch_to_str(epoch, fmt="%Y-%m-%d %H:%M:%S"):
      """
      Convert a unix timestamp into date string
  
      :param epoch: unix timestamp
      :param fmt: date format
      :return: formatted date from timestamp
      """
      return datetime.fromtimestamp(epoch).strftime(fmt)
  
imports: from collections import defaultdict
  import csv
  from datetime import datetime
  import json
  from math import radians, cos, sin, asin, sqrt
  import urllib2
  import numpy
label_desc: Use image node_id 3 for calling a global function with example usage: epoch_to_str(epoch, fmt) and returns: datetime