Section 270(3) of the Tax Law imposes liability for the tax upon the person or persons making or effectuating the sale or transfer, including the person or persons to whom the sale or transfer is made. Thus, both transferor and transferee (and also any agent or broker of either the transferor or the transferee) are liable, and if a transfer is made on the books of the corporation, it is also liable. The parties to a transaction may agree which of them shall bear this liability and payment of the tax by either discharges the liability of both. However, if the party who has agreed to pay the tax fails to do so, the other party is not exonerated from liability by such agreement and in such case payment may be enforced against either party.