docs: def dump_age(age=None):
      """Formats the duration as a base-10 integer.
  
      :param age: should be an integer number of seconds,
                  a :class:`datetime.timedelta` object, or,
                  if the age is unknown, `None` (default).
      """
      if age is None:
          return
      if isinstance(age, timedelta):
          # do the equivalent of Python 2.7's timedelta.total_seconds(),
          # but disregarding fractional seconds
          age = age.seconds + (age.days * 24 * 3600)
  
      age = int(age)
      if age < 0:
          raise ValueError("age cannot be negative")
  
      return str(age)