code: def map_mu_sigma_skw(self, mu, sigma, skw):
          
          delta = self._delta_skw(skw)
          a = self._alpha_delta(delta)
          w = self._w_sigma_delta(sigma, delta)
          e = self._e_mu_w_delta(mu, w, delta)
          return e, w, a
docs: map to parameters e, w, a
          :param mu: mean
          :param sigma: standard deviation
          :param skw: skewness
          :return: e, w, a