code: def gev_like(x, xi, mu=0, sigma=1):
      R
  
      return flib.gev(x, xi, mu, sigma)
docs: R"""
      Generalized Extreme Value log-likelihood
  
      .. math::
          pdf(x \mid \xi,\mu,\sigma) = \frac{1}{\sigma}(1 + \xi \left[\frac{x-\mu}{\sigma}\right])^{-1/\xi-1}\exp{-(1+\xi \left[\frac{x-\mu}{\sigma}\right])^{-1/\xi}}
  
      .. math::
          \sigma & > 0,\\
          x & > \mu-\sigma/\xi \text{ if } \xi > 0,\\
          x & < \mu-\sigma/\xi \text{ if } \xi < 0\\
          x & \in [-\infty,\infty] \text{ if } \xi = 0