code: def degenerate_like(x, k):
      R
      x = np.atleast_1d(x)
      return sum(np.log([i == k for i in x]))
docs: R"""
      Degenerate log-likelihood.
  
      .. math::
          f(x \mid k) = \left\{ \begin{matrix} 1 \text{ if } x = k \\ 0 \text{ if } x \ne k\end{matrix} \right.
  
      :Parameters:
        - `x` : Input value.
        - `k` : Degenerate value.