The credit union shall have a lien on the share accounts and accumulated dividends of a member for any sum owed the credit union by the member and for any loan endorsed by him. The credit union shall also have a right of immediate set-off with respect to every deposit account. The credit union may waive its right to a lien, to immediate set-off, to restrict withdrawals, or to any combination of such rights with respect to any share or deposit account or groups of such accounts.