Radiatively corrected shape function for inclusive heavy hadron decays

We discuss the nonperturbative and the radiative corrections to inclusive B decays from the point of view known from QED corrections to high energy ee~ processes. Here the leading contributions can be implemented through the so called radiator function which corresponds to the shape function known in heavy hadron decays. In this way some new insight into the origin of the shape function is obtained. As a by-product, a parametrization of the radiatively corrected shape function is suggested which can be implemented in Monte Carlo studies of inclusive heavy hadron decays.