What are the various ways by which there can be a discharge of the surety’s liability by revocation?

Section 130 Revocation of continuing guarantee- A continuing guarantee may at any time be revoked by the surety, as to future transactions, by notice to the creditor, Section 131Revocation of continuing guarantee by surety's death- he death of the surety operates, in the absence of any contract to the contrary, as a revocation of a continuing guarantee, so far as regards future transaction, Section 133  Discharge of surety by variance in terms of contract- Any variance, made without the surety’s consent, in the terms of the contract between the principal debtor and the creditor, discharges the surety as to transactions subsequent to the variance, Section 134  Discharge of surety by release or discharge of principal debtor-The surety is discharged by any contract between the creditor and the principal debtor, by which the principal debtor is released, or by any act or omission of the creditor, the legal consequence of which is the discharge of the principal debtor, Section 135 Discharge of surety when creditor compounds with, gives time to, or agrees not to sue, principal debtor- A contract between the creditor and the principal debtor, by which the creditor makes a composition with, or promises to give time to, or not to sue, the principal debtor, discharges the surety, unless the surety assents to such contract, Section 139   Discharge of surety of creditor's act or omission impairing surety's eventual remedy- If the creditor does any act which is inconsistent with the rights of the surety, or omits to do any act which his duty to the surety requires him to do, and the eventual remedy of the surety himself against the principal debtor is thereby impaired, the surety is discharged, Section 141 Surety's right to benefit of creditor's securities- A surety is entitled to the benefit of every security which the creditor has against the principal debtor at the time when the contract of suretyship is entered into, whether the surety knows of the existence of such security or not; and if the creditor loses, or, without the consent of the surety, parts with such security, the surety is discharged to the extent of the value of the security