More explanations on top of this page.
In the LibreOfficeDev Calc functions, parameters marked as "optional" can be left out only when no parameter follows. For example, in a function with four parameters, where the last two parameters are marked as "optional", you can leave out parameter 4 or parameters 3 and 4, but you cannot leave out parameter 3 alone.
Lakkaddaawwan 127 caalan barruuyyeessa arfii sirna keetiirratti hundaa'uu danda'a(fakkeenyaaf iso-8859-1, iso-8859-2, Windows-1252, Windows-1250), kanaaf fiduun hin danda'amu.