code: def apply_inverse(self, y):
          
          self._recompute()
          return self.solver.solve(self._process_input(y))
docs: Apply the inverse of the covariance matrix to a vector or matrix
  
          Solve ``K.x = y`` for ``x`` where ``K`` is the covariance matrix of
          the GP with the white noise and ``yerr`` components included on the
          diagonal.
  
          Args:
              y (array[n] or array[n, nrhs]): The vector or matrix ``y``
              described above.
  
          Returns:
              array[n] or array[n, nrhs]: The solution to the linear system.
              This will have the same shape as ``y``.
  
          Raises:
              ValueError: For mismatched dimensions.