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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 _highest_perm_from_iter(self, perm_iter):
 """Return the highest perm present in ``perm_iter`` or None if ``perm_iter`` is empty."""

        perm_set = set(perm_iter)
        for perm_str in reversed(ORDERED_PERM_LIST):
            if perm_str in perm_set:
                return perm_str