Determine if there is a subset of the given set with sum divisible by a given integer


I’ve been given a question to solve:

Given a set of non-negative distinct integers, and a value $ m$ , determine if there is a subset of the given set with sum divisible by $ m$ .

For this question the answer is here

I don’t understand the part after if DP[j]==True
what is actually the intuition behind this code. Please explain in detail.