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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _effective_perm_list_from_iter(self, perm_iter):
 """Return list of effective permissions for for highest permission in ``perm_iter``, ordered lower to higher, or None if ``perm_iter`` is empty."""

        highest_perm_str = self._highest_perm_from_iter(perm_iter)
        return (
            self._equal_or_lower_perm_list(highest_perm_str)
            if highest_perm_str is not None
            else None
        )