docs: def deriv2(self, p):
          """
          Second derivative of the Cauchy link function.
  
          Parameters
          ----------
          p: array-like
              Probabilities
  
          Returns
          -------
          g''(p) : array
              Value of the second derivative of Cauchy link function at `p`
          """
          a = np.pi * (p - 0.5)
          d2 = 2 * np.pi**2 * np.sin(a) / np.cos(a)**3
          return d2