Shortcut for getting the following passage identifier

        :rtype: CtsReference
        :returns: Following passage reference

def nextId(self):
        """ Shortcut for getting the following passage identifier

        :rtype: CtsReference
        :returns: Following passage reference
        """
        if self._next_id is False:
            # Request the next urn
            self._prev_id, self._next_id = self.getPrevNextUrn(reference=self.urn.reference)
        return self._next_id