def get_timedelta_second(self):
return self.__get_timedelta_sec(self.timedelta)<EOL>
:return: (|attr_end_datetime| - |attr_start_datetime|) as seconds
:rtype: float

:Sample Code:
    .. code:: python

        from datetimerange import DateTimeRange
        time_range = DateTimeRange("2015-03-22T10:00:00+0900", "2015-03-22T10:10:00+0900")
        time_range.get_timedelta_second()
:Output:
    .. parsed-literal::

        600.0