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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 get_vault_lookup_session(self):
 """Gets the OsidSession associated with the vault lookup service. return: (osid.authorization.VaultLookupSession) - a ``VaultLookupSession`` raise: OperationFailed - unable to complete request raise: Unimplemented - ``supports_vault_lookup() is false`` *compliance: optional -- This method must be implemented if ``supports_vault_lookup()`` is true.* """

        if not self.supports_vault_lookup():
            raise errors.Unimplemented()
        # pylint: disable=no-member
        return sessions.VaultLookupSession(runtime=self._runtime)