What is Advance Pricing Agreement (APA) under section 92CC of the Income-Tax Act, 1961? Discuss and explain the validity and the binding nature of APA.

Advance Pricing Agreement (APA) as per section 92CC is an agreement entered into between a taxpayer and a taxing authority (Board) on an appropriate transfer pricing methodology for fixing the arm's length price 'ALP' for a set of transactions over a fixed period of time in future. The Advance Pricing Agreement shall be valid for a period as specified in the Advance Pricing Agreement. However, this period will not be more than 5 consecutive previous years. Advance Pricing Agreement shall be binding on: (a) the person in whose case, and in respect of the transaction in relation to which, the agreement has been entered into; and (b) on the Principal Commissioner or Commissioner, and the income-tax authorities subordinate to him, in respect of the said person and the said transaction. However the advance pricing agreement shall not be binding if there is a change in law or facts having bearing on the agreement so entered into.