code: def H10(self):
          "Difference variance."
          c = (self.rlevels * self.p_xminusy).sum(1)
          c1 = np.tile(c, (self.nlevels,1)).transpose()
          e = self.rlevels - c1
          return (self.p_xminusy * e ** 2).sum(1f H10(self):
          "Difference variance."
          c = (self.rlevels * self.p_xminusy).sum(1)
          c1 = np.tile(c, (self.nlevels,1)).transpose()
          e = self.rlevels - c1
          return (self.p_xminusy * e ** 2).sum(1)
docs: Difference variance.