In addition, agreements concluded by minors may be considered as not concluded; However, some contracts with minors that have the consent of a parent or legal guardian may be enforceable. A contract may also be null and void due to the impossibility of performing it. For example, a contract between an illegal drug supplier and a dealer is a priori unenforceable because of the illegal nature of the agreed activity. An agreement for the performance of an illegal act is an example of an invalid agreement. For example, a contract between drug traffickers and buyers is a void contract simply because the terms of the contract are illegal. In such a case, neither party can go to court to enforce the contract. An agreement not concluded is not concluded from the outset, that is: from the outset, while a countervailable contract may be challenged by one or all of the parties. . . .