In the case of an action for failure to fulfil obligations, it is permissible to prove the evolution of the activity in order to interpret the ambiguities contained in the contract, but not to make an amendment or opposition to the provisions of the Treaty. An apparently clear deadline for concluding the contract could prove problematic a posteriori. UZK § 1-303 (b). The « conduct of business », as defined in subsection (b), is literally limited to a succession of conduct between the parties prior to the agreement. However, a succession of behaviors at the end of or below the agreement is a « performance evolution ».  The history of the remedy is often useful in determining the scope of a patent, as it shows the course of management of the Patent Office, which may have a particular meaning for the terms, or a position that the applicant has taken to ensure that the patent is granted.  However, proof of trade is prohibited if it is « carefully denied » in the parties` treaty by « specific and unequivocal » language.  « Transaction » means a series of conduct relating to prior transactions between the parties to a given transaction which, by law, must be considered as a common basis for understanding the interpretation of their expressions and other conduct. Even if, according to the Parol rule of proof, words and terms cannot be refuted by extrinsic evidence of a prior or simultaneous agreement in a memorandum conceived as the definitive expression of the agreement reached by the parties, extrinsic evidence in the form of course transactions may nevertheless be used to explain or supplement the letter.
An integration clause in a contract stipulating that the parties intend to make the writing a complete and exclusive declaration of the terms of the contract is not sufficient to deny the importance of the trade « because they form an integral part of the treaty to the point that they are not normally excluded by the general language of the merger clause ».  (f) Subject to sections 2 to 209, the evolution of benefits is relevant to demonstrate a waiver or modification of a time limit that is inconsistent with the evolution of the benefit. The concept of conduct of transactions is defined as follows in the Single Commercial Code: (a) a « performance evolution » is a succession of behaviours between the parties to a given transaction that exists when: (1) the agreement of the parties regarding the transaction involves repeated opportunities for performance by a party; and (2) the consideration, knowing the nature of the performance and the possibility, accepts the performance or is without opposition to it. If, in view of the explicit terms of the agreement, it is still not possible to determine its meaning, the Tribunal may be prepared to suggest certain conditions.20 However, courts are reluctant to depart from the explicit wording, particularly where the contract is detailed and appears to be complete. In practice, situations in which the courts are willing to involve a contract term are limited.. . . .