Interpretation and meaning of "a@0==0" in python

I cannot understand the meaning of this condition "((a+0!=0) or (a@0==0))" in the code bellow. This code test if the input year is a leap year.

a = eval(input('Enter a year :'))

if (a%4==0) and ((a+0!=0) or (a@0==0)): print(a,"is a leap year") else: print(a,"is not a leap year")

Thank you for your help.