how can I solve this error :
igmoid_derivative(t_x) = [ 0 -2 -6]
NameError Traceback (most recent call last)
in
2 print ("sigmoid_derivative(t_x) = " + str(sigmoid_derivative(t_x)))
3
----> 4 sigmoid_derivative_test(sigmoid_derivative)
NameError: name ‘sigmoid_derivative_test’ is not defined