code: def propose_live(self):
          
  
          i = self.rstate.randint(self.nlive)
          u = self.live_u[i, :]
  
          # Choose axes.
          if self.sampling in ['rwalk', 'rstagger', 'rslice']:
              ax = self.ell.axes
          elif self.sampling == 'slice':
              ax = self.ell.paxes
          else:
              ax = np.identity(self.npdim)
  
          return u, ax
docs: Return a live point/axes to be used by other sampling methods.