f(z) = ((conjugate(z))^ 2)/z, if z ≠ 0 and f(0) = 0. check whether the function is analytic or not.

I could not understand ,here z ≠0 is given but at the same time the value of f(z) at z=0 is given to be 0. and if the function is not defined at z=0 , then why to bother for the function to be analytic at origin?