code: def dot_solve(self, y):
          r
          return np.dot(y.T, cho_solve(self._factor, y))
docs: r"""
          Compute the inner product of a vector with the inverse of the
          covariance matrix applied to itself:
  
          .. math::
  
              y\,K^{-1}\,y
  
          Args:
              y (ndarray[nsamples]): The vector :math:`y`.