In what order shall the judge apply the following, according to the Turkish Civil Code?

I. Deciding in accordance with the customary law

II$.$ Laying down a rule as he were legislator

III. Ascertaining written legal rules applicable

III$-II-$I

$I-$III$-II$

$II-|-$ III $|$

III$-I-II$

$|I-$ III$-$I $|$