Returns ``True`` if this interval starts at the given time point.

        :param time_point: the time point to test
        :type  time_point: :class:`~aeneas.exacttiming.TimeValue`
        :raises TypeError: if ``time_point`` is not an instance of ``TimeValue``
        :rtype: bool

def starts_at(self, time_point):
        """
        Returns ``True`` if this interval starts at the given time point.

        :param time_point: the time point to test
        :type  time_point: :class:`~aeneas.exacttiming.TimeValue`
        :raises TypeError: if ``time_point`` is not an instance of ``TimeValue``
        :rtype: bool
        """
        if not isinstance(time_point, TimeValue):
            raise TypeError(u"time_point is not an instance of TimeValue")
        return self.begin == time_point