Legal Document Circumventing Interest

I copied this template from R. Jacob of Orléans. He permitted borrowing at interest by means of this document, which reads as follows:

I, the undersigned, hereby fully certify that I owe the sum of ____ to So-and-So, as he lent me in the month of ____, in the year ____, according to the counting of the years used in the city of ____. I am hereby obligated to repay him within fifteen days of his demand, and to bring the sum to him in the city of ____, as determined by him. For the period that I delay and fail to repay him, I must give him a gift, each and every week that I postpone repayment from the day of the loan until the day of repayment, of ____ coins in the currency of ____. This applies to each and every week; I must deliver the entire sum to his possession in the city of ____, as determined by him within fifteen days of his demand.

As long as this document is in his possession, I am not to be deemed credible if I submit any form of claim regarding all that is clarified in this deed. Rather, he is credible in his claim against me without having to take an oath, that I owe him everything as set out in this deed. I must accept his credibility without him having to take an oath, as per our stipulation when he transferred his money to me. This condition and certification are executed in accordance with the enactment of the sages, and the document negates any declaration to the contrary, and it is not like a transaction with questionable consent, nor like a template of documents. I have signed beneath my confession and stipulation, so that he should have the document in his possession to serve in his advantage and as proof, and my signature will testify against me with the power of one hundred valid witnesses. He may likewise sign the document himself, together with other witnesses.