The contract shall be presumed to be an equitable mortgage, in any of the following cases: (1) When the price of a sale with right to repurchase is unusually inadequate; (2) When the vendor remains in possession as lessee or otherwise; (3) When upon or after the expiration of the right to repurchase another instrument extending the period of redemption or granting a new period is executed; (4) When the purchaser retains for himself a part of the purchase price; (5) When the vendor binds himself to pay the taxes on the thing sold; (6) In any other case where it may be fairly inferred that the real intention of the parties is that the transaction shall secure the payment of a debt or the performance of any other obligation. In any of the foregoing cases, any money, fruits, or other benefit to be received by the vendee as rent or otherwise shall be considered as interest which shall be subject to the usury laws. (n)