docs: def dump(props, fp, separator='=', comments=None, timestamp=True,
           sort_keys=False):
      """
      Write a series of key-value pairs to a file in simple line-oriented
      ``.properties`` format.
  
      :param props: A mapping or iterable of ``(key, value)`` pairs to write to
          ``fp``.  All keys and values in ``props`` must be text strings.  If
          ``sort_keys`` is `False`, the entries are output in iteration order.
      :param fp: A file-like object to write the values of ``props`` to.  It must
          have been opened as a text file with a Latin-1-compatible encoding.
      :param separator: The string to use for separating keys & values.  Only
          ``" "``, ``"="``, and ``":"`` (possibly with added whitespace) should
          ever be used as the separator.
      :type separator: text string
      :param comments: if non-`None`, ``comments`` will be written to ``fp`` as a
          comment before any other content
      :type comments: text string or `None`
      :param timestamp: If neither `None` nor `False`, a timestamp in the form of
          ``Mon Sep 02 14:00:54 EDT 2016`` is written as a comment to ``fp``
          after ``comments`` (if any) and before the key-value pairs.  If
          ``timestamp`` is `True`, the current date & time is used.  If it is a
          number, it is converted from seconds since the epoch to local time.  If
          it is a `datetime.datetime` object, its value is used directly, with
          naïve objects assumed to be in the local timezone.
      :type timestamp: `None`, `bool`, number, or `datetime.datetime`
      :param bool sort_keys: if true, the elements of ``props`` are sorted
          lexicographically by key in the output
      :return: `None`
      """
      if comments is not None:
          print(to_comment(comments), file=fp)
      if timestamp is not None and timestamp is not False:
          print(to_comment(java_timestamp(timestamp)), file=fp)
      for k,v in itemize(props, sort_keys=sort_keys):
          print(join_key_value(k, v, separator), file=fp)