Otherwise, when a State withdraws from a multilateral treaty, this treaty shall remain in force between the other parties, unless it can or can be interpreted as agreed between the other States parties. [Citation required] Australian contracts generally fall into the following categories: extradition, postal agreements and payment vouchers, trade and international conventions. The language of treaties should be interpreted, like that of a law or contract, if the wording was not clear or if it was not immediately clear how it was to be applied in a perhaps unforeseen circumstance. The Vienna Convention provides that contracts must be interpreted “in good faith” on the basis of “the usual importance given to contractual conditions in their context and in the light of their purpose and purpose”. International legal experts also often invoke the “principle of maximum efficiency”, which interprets the contractual language in such a way that it has the maximum force and effect to establish obligations between the parties. Prior to 1871, the U.S. government regularly entered into contracts with Native Americans, but the Indian Appropriations Act of March 3, 1871 (chap. .