How to find all maximas if x and y values of the function are given as np.array

I have two numpy arrays x and y, I have plotted a curve with these values. Now I want to find all the values of x where local maxima exists on that curve. How it will be done?

Please give a method to fit the best possible curve with these x and y values and the values of x (or the indices of the value of x in array x) where local maxima exists.