(4) An estimate shall be made by the official assignee of the value of any debt or liability provable as aforesaid which by reason of its being subject to any contingency or contingencies, or for any other reason, does not bear a certain value: Provided that if in his opinion the value of the debt or liability is incapable of being fairly estimated, he shall issue a certificate to that effect, and thereupon the debt or liability shall be deemed to be a debt not provable in insolvency. Explanation.-For the purposes of this section" liability" includes any compensation for work or labour done, any obligation or possibility of an obligation to pay money or money' s worth on the breach of any express or implied covenant, contract, agreement or undertaking, whether the breach does or does not occur, or is or is not likely to occur or capable of occurring, before the discharge of the debtor, and generally it includes any express or implied engagement, agreement or undertaking to pay, or capable of resulting in the payment of, money or money' s worth, whether the payment is, as respects amount, fixed or unliquidated; as respects time, present or future, certain or dependent on any contingency or contingencies; as to mode of valuation, capable of being ascertained by fixed rules, or as matter of opinion.”
