def _tzstr(self, sep=":"):
        """Return formatted timezone offset (+xx:xx) or None."""
        off = self._utcoffset()
        if off is not None:
            if off < 0:
                sign = "-"
                off = -off
            else:
                sign = "+"
            hh, mm = divmod(off, 60)
            assert 0 <= hh < 24
            off = "%s%02d%s%02d" % (sign, hh, sep, mm)
        return off
def _tzstr(self, sep=":"):
        """Return formatted timezone offset (+xx:xx) or None."""
        off = self._utcoffset()
        if off is not None:
            if off < 0:
                sign = "-"
                off = -off
            else:
                sign = "+"
            hh, mm = divmod(off, 60)
            assert 0 <= hh < 24
            off = "%s%02d%s%02d" % (sign, hh, sep, mm)
        return off
Return formatted timezone offset (+xx:xx) or None.