Check that the interval of the given fragment
        is within the boundaries of the list.
        Raises an error if not OK.

def _check_boundaries(self, fragment):
        """
        Check that the interval of the given fragment
        is within the boundaries of the list.
        Raises an error if not OK.
        """
        if not isinstance(fragment, SyncMapFragment):
            raise TypeError(u"fragment is not an instance of SyncMapFragment")
        interval = fragment.interval
        if not isinstance(interval, TimeInterval):
            raise TypeError(u"interval is not an instance of TimeInterval")
        if (self.begin is not None) and (interval.begin < self.begin):
            raise ValueError(u"interval.begin is before self.begin")
        if (self.end is not None) and (interval.end > self.end):
            raise ValueError(u"interval.end is after self.end")