code: def _parse_timestamp(timestamp):
          
          if timestamp:
              try:
                  return aniso8601.parse_datetime(timestamp)
              except AttributeError:
                  # raised by aniso8601 if raw_timestamp is not valid string
                  # in ISO8601 format
                  try:
                      return datetime.utcfromtimestamp(timestamp)
                  except:
                      # relax the timestamp a bit in case it was sent in millis
                      return datetime.utcfromtimestamp(timestamp/1000)
  
          raise ValueError('Invalid timestamp value! Cannot parse from either ISO8601 string or UTC timestamp.')
docs: Parse a given timestamp value, raising ValueError if None or Flasey