How are they converting integers to binary base


#1

class Solution:
# @param A : tuple of integers
# @return an integer
def hammingDistance(self, A):
res = 0
n = len(A)
MOD = 1000000007

    for i in range(32):
        cnt = 0
        for j in range(n):
            if A[j] & (1 << i):
                cnt += 1
        res += (cnt * (n - cnt) * 2) % MOD
    
    return res % MOD

where is it becoming binary form for further calculations???