code: def as_hyperbola(self, rotated=False):
          
          idx = N.diag_indices(3)
          _ = 1/self.covariance_matrix[idx]
          d = list(_)
          d[-1] *= -1
  
          arr = N.identity(4)*-1
          arr[idx] = d
          hyp = conic(arr)
          if rotated:
              R = augment(self.axes)
              hyp = hyp.transform(R)
          return hyp
docs: Hyperbolic error area