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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 _clean_key_expiration_option(self):
 """validates the expiration option supplied"""

        allowed_entry = re.findall('^(\d+)(|w|m|y)$', self._expiration_time)
        if not allowed_entry:
            raise UsageError("Key expiration option: %s is not valid" % self._expiration_time)