docs: def _short_ts_regexp():
  	'''Generates regexp for parsing of
  		shortened relative timestamps, as shown in the table.'''
  	ts_re = ['^']
  	for k in it.chain(_short_ts_days, _short_ts_s):
  		ts_re.append(r'(?P<{0}>\d+{0}\s*)?'.format(k))
  	return re.compile(''.join(ts_re), re.I | re.U)