code: def _h_function(self,h):
          
  
          hh = h / self.a
          h = self.contribution * (1.0 - (hh * (1.5 - (0.5 * hh * hh))))
          h[hh > 1.0] = 0.0
          return h
docs: private method for the spherical variogram "h" function
  
          Parameters
          ----------
          h : (float or numpy.ndarray)
              distance(s)
  
          Returns
          -------
          h_function : float or numpy.ndarray
              the value of the "h" function implied by the SphVario