Problem in the coding given for calculation of dz2 and dz1

Course Q&A Deep Learning Specialization Improving Deep Neural Networks: Hyperparameter tun
1

In the programming assignments these are the codes given to us for dz2 and dz1. what is the role of np.int64(A2>0). To me it seems this is the value of g’(z). is it . how it is?

dZ2 = np.multiply(dA2, np.int64(A2 > 0))

dZ1 = np.multiply(dA1, np.int64(A1 > 0))

2

This is a duplicate thread: I already answered on the other copy.