Not Able To Understand How This Submission Is Valid

Referring to this submission: MachineHack/Hackathon_Solutions/renew_power_hiring_hackathon/Andrey_Bessalov_ReNew_machinehack_code_Андрей_Бессалов.ipynb

He is fitting the model on only K-fold=0 then using it to make predictions then making a submission file. This is not the complete solution I think so. Can you please look into it?