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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 op_token(self, display_name, opt):
 """Return a properly annotated token for our use. This token will be revoked at the end of the session. The token will have some decent amounts of metadata tho."""

        args = {
            'lease': opt.lease,
            'display_name': display_name,
            'meta': token_meta(opt)
        }
        try:
            token = self.create_token(**args)
        except (hvac.exceptions.InvalidRequest,
                hvac.exceptions.Forbidden) as vault_exception:
            if vault_exception.errors[0] == 'permission denied':
                emsg = "Permission denied creating operational token"
                raise aomi.exceptions.AomiCredentials(emsg)
            else:
                raise

        LOG.debug("Created operational token with lease of %s", opt.lease)
        return token['auth']['client_token']