However, having found the border closed, as he asserted, even though he did not present any evidence that proofs his statement, he decided to wait there for it to open during 63 days, when he decided to turn around and return to The Gambia where the goods came to be re-certified as unfit for consumption. In this case, it remains to be ascertained whether the closure of the border (unlawful act) was the appropriate cause for the production of the damage. According to the legal theory of proper causality, in order for a fact to be the caused of a damage, it is not necessary that on its own, without the collaboration of others, it causes the damage, but it must be condition of the damage or one of the conditions of the damage, provided that the fact is objectively appropriate to the production of that damage (See Antunes Varela in "das Obrigações em Geral Vol. I. 2ª Ed. 754 e ss. Almeida e Costa in “Direito das Obrigações” 5ª ed., 634 e ss e Galvão Telles, in “Direito das Obrigações” 6ª ed. 408). According to this theoretical construction it can not be abstracted from the factual process that, in particular, it led to the damage. In this case, the applicant claimed that on 18 March 2016 the defendants' agents closed the border by not allowing him to pass with his three lorries loaded with smoked fish, and that he waited on that frontier for 63 days, believing that the closure was temporary, until, on 20 May, when he decided to turn around and return to The Gambia. It can not be taken as proved the applicant´s stay at the border for 63 days, since he did not present any evidence. However, even if the applicant would have proved such fact, it could still be concluded that if he could have been diligent and adopted the behavior of an average man or of a "bonus pater family" (a good family father), the applicant could have avoided the damage, by having turned around and gone back to The Gambia on a timely manner, for he knew the perishable nature of the commodity he carried. Therefore, it is not acceptable that the applicant remained at the frontier for 63 days as he claimed, exposing the goods he was carrying to the conditions he describes, thus contributing to its deterioration, and then impute the damage to the Defendant State. 25