Husbandry is - in so many words - the conditions in which you keep your snake. "Proper husbandry" is keeping your pet in a healthy, safe, and correct environment. For ball pythons this is 90 degree hot spot, 80 degree ambient temps, 50-60% humidity (higher during shed), two tight-fitting hides, correct prey, and all the other things listed in the caresheet.
Hope that helps!