Specific Relief Act (47 of 1963) , S.20— Agreement to sell - Suit for specific performance - Stipulation in agreement that vendor and purchaser would not be entitled to refuse to sell or buy disputed property - Intention of parties was to perform contract - In such case, specific performance of contract ought to be enforced notwithstanding penal clause relating to payment by vendor of double the advance money to purchaser in case of breach - Sum named in contract as amount to be paid in case of its breach would be only for purpose of securing performance of contract and not for purpose of giving to vendor an option of paying money in lieu of specific performance. (Para 12)